SGK1
Serine/threonine-protein kinase Sgk1 also known as serum and glucocorticoid-regulated kinase 1 is an enzyme that in humans is encoded by the SGK1 gene.
SGK1 belongs to a subfamily of serine/threonine kinases that is under acute transcriptional control by several stimuli, including serum and glucocorticoids. The kinase is activated by insulin and growth factors via phosphatidylinositide-3-kinase, phosphoinositide-dependent protein kinase PDPK1 and mammalian target of rapamycin mTORC2.[5][6] It has been shown to "regulate several enzymes and transcription factors; SGK1 contributes to the regulation of transport, hormone release, neuroexcitability, inflammation, cell proliferation and apoptosis".[5][6] SGK1 increases the protein abundance and/or activity of a variety of ion channel, carriers, and the Na+/K+-ATPase. Over the past few years, there has been increasing evidence that SGK1 expression is regulated during both discrete developmental stages and pathological conditions such as hypertension, diabetic neuropathy, ischemia, trauma, and neurodegenerative diseases.[7]
Function
[edit]This gene encodes a serine/threonine protein kinase that plays an important role in cellular stress response. This kinase activates certain potassium, sodium, and chloride channels, suggesting an involvement in the regulation of processes such as cell survival, neuronal excitability, and renal sodium excretion.
Ion channel and transporter regulation
[edit]SGK1 has been shown to regulate the following ion channels:
- Epithelial Na+ channel ENaC[8][9]
- Renal outer medullary K+ channel KCNJ1 (ROMK1)[6][10]
- Renal epithelial Ca2+ channel TRPV5[6][11][12]
- Ubiquitous Cl− channel CLCN2 (ClC2)[6][13]
- Cardiac voltage-gated Na+ channel SCN5A[14][15]
- Cardiac and epithelial K+ channels KCNE1/KCNQ1[15][16]
- Voltage-gated K+ channels Kv1.3, Kv1.5, and Kv4.3[15][17]
- Glutamate Receptors [6][18]
The following carriers and pumps are influenced by SGK1:
Regulation of cell volume
[edit]SGK1 is upregulated by osmotic and isotonic cell shrinkage. "It is tempting to speculate that SGK1-dependent regulation of cation channels contributes to the regulation of cell volume, which involves cation channels in a variety of cells".[21] The entrance of NaCl and osmotically driven water into cells leads to an increase in the cell's regulatory cell volume. This occurs as the entrance of Na+ depolarizes the cell, thus allowing the parallel entrance of Cl−. SGK1 has also been shown to increase the activity of cell volume-regulated Cl− channel ClC2.[13] The activation of these Cl− channels result in the exit of Cl− and eventually the exit of K+, and the cellular loss of KCl results in a decrease of regulatory cell volume.
However, the functional significance of SGK1 in cell volume regulation, along with its stimulation of cation channels, is still not clearly understood. "Moreover, the molecular identity of the cation channels and the mechanisms of their regulation by glucocorticoids and osmotic cell shrinkage have remained elusive".[21] The following observations seem to have conflicting results, as one suggests a role of SGK1 by cell shrinkage and regulatory cell volume increase [22] while the other suggests regulatory cell volume decrease. It is possible that SGK1 works to maintain regulatory cell volume by increasing the cell's ability to cope with alterations in cell volume.[6][21]
Dehydration
[edit]The hydration state of the brain is critical to neuronal function. One way hydration modifies cerebral function is by influencing neuronal and glial cell volume. Dehydration alters the expression of a wide variety of genes including SGK1. "It has been shown that SGK1-sensitive functions contribute significantly to the altered function of the dehydrated brain".[5]
Cell proliferation and apoptosis
[edit]SGK1 has been shown to inhibit apoptosis. "The antiapoptotic effect of SGK1 and SGK3 has been attributed in part to phosphorylation of forkhead transcription factors".[5] It is suggested that proliferative signals transport SGK1 into the nucleus, and the effect of SGK1 on cell proliferation may be due to its ability to regulate Kv1.3.[5][15][17] "The upregulation of Kv1.3 channel activity may be important for the proliferative effect of growth factors, as IGF-I induced cell proliferation is disrupted by several blockers of Kv channels".[17]
SGK1 knockout mice show seemingly normal development.[23] "Thus SGK1 is either not a crucial element in the regulation of cell proliferation or apoptosis, or related kinase(s) can effectively replace SGK1 function in the SGK1 knockout mice".[5]
Memory formation
[edit]It has been suggested that this kinase plays a critical role in long-term memory formation.[24] Wild-type SGK1 improves the learning abilities of rats. On the other hand, the transfection of inactive SGK1 decreases their abilities in spatial, fear-conditioning, and novel object recognition learning.[5][6]
The effect of glutamate receptors may also impact the role of SGK1 in memory consolidation. "SGK isoforms upregulate AMPA and kainate receptors and thus are expected to enhance the excitatory effects of glutamate".[5] Synaptic transmission and hippocampal plasticity are both affected by kainate receptors. A lack of SGK may reduce glutamate clearance from the synaptic cleft leading to altered function or regulation of glutamate transporters and receptors; This could result in increasing neuroexcitotoxicity and eventually neuronal cell death.[5][6][21]
Long-term potentiation
[edit]SGK has been to shown to facilitate the expression of long-term potentiation in hippocampal neurons and neuronal plasticity. SGK mRNA expression in the hippocampus in enhanced by the AMPA receptor. Moreover, "AMPA receptor-mediated synaptic transmission is closely associated with the late phase of long-term potentiation".[24]
Transcription
[edit]The human isoform of SGK1 has been identified as a cell volume-regulated gene that is transcriptionally upregulated by cell shrinkage. "The regulation of SGK1 transcript levels is fast; appearance and disappearance of SGK1 mRNA require <20 min".[22] Its transcription is increasingly expressed by serum and glucocorticoids, and transcriptional changes in SGK1 expression occur in correlation with the appearance of cell death.[7] Signaling molecules involved in transcriptional regulation of SGK1 include cAMP, p53, and protein kinase C. As SGK1 transcription is sensitive to cell volume, cerebral SGK1 expression is upregulated by dehydration.
"SGK1 expression is controlled by a large number of stimuli including serum, IFG-1, oxidative stress, cytokines, hypotonic conditions, and glucocorticoids".[7] Mineralocorticoids, gonadotropins, fibroblast and platelet-derived growth factor, and other cytokines are also understood to stimulate SGK1 transcription.[15][21] The upregulation of SGK1 in various neurodegenerative diseases correlates directly with these stimuli, as alterations in these stimuli accompany many neurodegenerative diseases.
- Glucocorticoids: SGK expression is mainly regulated by glucocorticoids.[24] Glucocorticoids have been shown to enhance memory consolidation in a range of exercises in animals. Glucocorticoid hormones are also consistently increased in patients with severe depression. It has been shown that chronically high concentrations of glucocorticoids impair hippocampal neurogenesis by activating the glucocorticoid receptor (GR). Indeed, "SGK1 is a key enzyme involved in the downstream mechanisms by which glucocorticoids reduce neurogenesis and in the upstream potentiation and maintenance of GR function, even after glucocorticoid withdrawal".[25]
- Oxidative Stress: Oxidative stress is a common component of the neurodegenerative process. "It has been shown to induce SGK expression through a p38/MAPK-dependent pathway, with SGK1 responding rapidly and transiently to changes in stress".[26]
- DNA Damage: "SGK1 gene transcription is stimulated by DNA damage through p53 and activation of extracellular signal-regulated kinase (ERK1/2)".[15][21]
Other stimuli include neuronal injury, neuronal excitotoxicity, increased cytosolic Ca2+ concentration, ischemia, and nitric oxide.
Metabolism
[edit]SGK1, along with SGK3, has been shown to stimulate the absorption of intestinal glucose by the Na+-glucose cotransporter SGLT1. "SGK1 also favors cellular glucose uptake from the circulation into several tissues including brain, fat, and skeletal muscle".[19] SGK1 also plays a critical role in the stimulation of cellular glucose uptake by insulin. Accordingly, SGK1 does not only integrate effects of mineralocorticoids and insulin on renal tubular Na+ transport but similarly affects glucose transport".[21]
Kidney
[edit]By aldosterone, insulin, and IGF-I, SGK1 has been suggested to influence the regulation of ENaC and participate in the regulation of renal Na+ excretion.[27][28] It has been indicated "that activation of ENaC by ADH or insulin depends on SGK1 and/or reflects independent pathways induced by ADH/insulin and SGK1 that converge on the same target structures".[21] Renal ENaC function, along with renal mineralocorticoid action, is also partly dependent upon the presence of SGK1. One study also determined that SGK1 has a critical role in insulin-induced renal Na+ retention.[29]
"SGK1 plays at least a dual role in mineralocorticoid-regulated NaCl homeostasis. SGK1 dependence of both NaCl intake and renal NaCl reabsorption suggests that excessive SGK1 activity leads to arterial hypertension by simultaneous stimulation of oral NaCl intake and renal NaCl retention".[21]
Gastrointestinal
[edit]Including having a high expression in enterocytes, SGK1 is highly expressed in the gastrointestinal tract.[21][30] It has been suggested that glucocorticoids are the primary stimulant of intestinal SGK1 expression. Unlike in renal function, ENaC regulation in the colon is currently not fully understood. At the current time, it seems SGK1 is not required for stimulation of ENaC in the distal colon.[21]
Cardiovascular
[edit]The heart is one of the many tissues with high SGK1 expression. As SGK1 affects both Na+ intake and renal+ excretion, the regulation of blood pressure could be influenced by SGK1-induced salt imbalance. Activated SGK1, due to insulin, may lead to Na+ reabsorption and consequently higher blood pressure.[21][31]
SGK1 has been shown to impact the QT interval of the heart electrical cycle. As the QT interval represents the electrical depolarization and repolarization of the left and right ventricles, "SGK1 may have the capacity to shorten Q-T".[21] "In support of this, a gene variant of SGK1, presumably conferring enhanced SGK1 activity is indeed associated with a shortened Q-T interval in humans".[32]
Clinical significance
[edit]A gain-of-function mutation in SGK1, or serum and glucocorticoid-inducible kinase 1, can lead to a shortening of the QT interval, which represents the repolarization time of the cardiac cells after a cardiac muscle contraction action potential.[33] SGK1 does this by interacting with the KvLQT1 channel in cardiac cells, stimulating this channel when it is complex with KCNE1. SGK1 stimulates the slow delayed rectifier potassium current through this channel by phosphorylating PIKfyve, which then makes PI(3,5)P2, which goes on to increase the RAB11-dependent insertion of the KvLQT1/KCNE1 channels into the plasma membrane of cardiac neurons.[34] SGK1 phosphorylates PIKfyve, which results in regulated channel activity through RAB11-dependent exocytosis of these KvLQT1/KCNE1-containing vesicles. Stress-induced stimuli have been known to activate SGK1, which demonstrates how Long QT Syndrome is brought on by stressors to the body or to the heart itself. By increasing the insertion of KVLQT1/KCNE1 channels into the plasma membrane through an alteration of trafficking within the cell, SGK1 is able to enhance the slow delayed potassium rectifier current in the neurons.[33]
Role in neuronal disease
[edit]Two majors components of SGK1 expression, oxidative stress and an increase in glucocorticoids, are common components of the neurodegenerative process. "Studies suggest that SGK1 is an important player in cell death processes underlying neurodegerative diseases, and its role seems to be neuroprotective".[7]
AMPA and Kainate receptors are regulated by SGK isoforms.[18] AMPA receptor activation is key for ischemic-induced cell death.[35] Where changes in GluR2 levels are observed, "it has been suggested that disturbed SGK1-dependent regulation of AMPA and kainate receptors could participate in the pathophysiology of Amyotrophic lateral sclerosis (ALS), schizophrenia, and epilepsy".[5] Kainate receptors are thought to be involved in epileptic activity.[21]
Glutamate transporters act to remove glutamate from extracellular space. A lack of SGK1 may prevent glutamate activity while at the same time decreasing glutamate clearance from the synaptic cleft.[18] "As glutamate may exert neurotoxic effects, altered function or regulation of glutamate transporters and glutamate receptors may foster neuroexcitotoxicity".[21]
Huntingtin
[edit]Counteracting huntingtin toxicity, SGK1 has been found to phosphorylate huntingtin.[36] "Genomic upregulation of SGK1 coincides with the onset of dopaminergic cell death in a model of Parkinson's disease".[21][37] However, at the current time, it is unclear whether SGK1 prevents or motivates cell death. An excessive expression of SGK1 has also been observed in Rett syndrome (RTT), which is a disorder of severe mental retardation.[38]
SGK1 is suggested to take part in the signaling of brain-derived neurotrophic factor (BDNF). It is known that BDNF is involved in neuronal survival, plasticity, mood, and long-term memory. "SGK1 could participate in the signaling of BDNF during schizophrenia, depression, and Alzheimer's disease".[5] "Moreover, BDNF concentrations are modified after major psychiatric treatment strategies",[21] including antidepressants and electroconvulsive therapy.
Other neuronal diseases
[edit]- Tau protein: Tau protein is phosphorylated by SGK1. SGK1 may contribute to Alzheimer's disease, as it is paralleled by hyperphosphorylation of tau.[21]
- CreaT: "The ability of SGK1 to upregulate the creatine transporter CreaT may similarly be of pathological significance, as individuals with defective CreaT have been shown to suffer from mental retardation".[20][21]
- SKG1 mRNA: As SGK1 deficiency is simultaneously paired with insufficient glucocorticoid signaling, it has been suggested that it may participate in major depressive disorder. "A study looking at SGK1 mRNA expression in depressed patients found that depressed patients had significantly higher SGK1 mRNA levels".[25]
Interactions
[edit]SGK has been shown to interact with:
References
[edit]- ^ a b c GRCh38: Ensembl release 89: ENSG00000118515 – Ensembl, May 2017
- ^ a b c GRCm38: Ensembl release 89: ENSMUSG00000019970 – Ensembl, May 2017
- ^ "Human PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
- ^ "Mouse PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
- ^ a b c d e f g h i j k Lang F, Strutz-Seebohm N, Seebohm G, Lang UE (Sep 2010). "Significance of SGK1 in the regulation of neuronal function". The Journal of Physiology. 588 (Pt 18): 3349–3354. doi:10.1113/jphysiol.2010.190926. PMC 2988501. PMID 20530112.
- ^ a b c d e f g h i Lang F, Shumilina E (Jan 2013). "Regulation of ion channels by the serum- and glucocorticoid-inducible kinase SGK1". FASEB Journal. 27 (1): 3–12. doi:10.1096/fj.12-218230. PMID 23012321. S2CID 41053033.
- ^ a b c d Schoenebeck B, Bader V, Zhu XR, Schmitz B, Lübbert H, Stichel CC (Oct 2005). "Sgk1, a cell survival response in neurodegenerative diseases". Molecular and Cellular Neurosciences. 30 (2): 249–264. doi:10.1016/j.mcn.2005.07.017. PMID 16125969. S2CID 31687862.
- ^ Loffing J, Zecevic M, Féraille E, Kaissling B, Asher C, Rossier BC, Firestone GL, Pearce D, Verrey F (Apr 2001). "Aldosterone induces rapid apical translocation of ENaC in early portion of renal collecting system: possible role of SGK". American Journal of Physiology. Renal Physiology. 280 (4): F675–F682. doi:10.1152/ajprenal.2001.280.4.f675. PMID 11249859. S2CID 27451336.
- ^ Kuntzsch D, Bergann T, Dames P, Fromm A, Fromm M, Davis RA, Melzig MF, Schulzke JD (2012). "The plant-derived glucocorticoid receptor agonist Endiandrin A acts as co-stimulator of colonic epithelial sodium channels (ENaC) via SGK-1 and MAPKs". PLOS ONE. 7 (11): e49426. Bibcode:2012PLoSO...749426K. doi:10.1371/journal.pone.0049426. PMC 3496671. PMID 23152905.
- ^ Wald H, Garty H, Palmer LG, Popovtzer MM (Aug 1998). "Differential regulation of ROMK expression in kidney cortex and medulla by aldosterone and potassium". The American Journal of Physiology. 275 (2 Pt 2): F239–F245. doi:10.1152/ajprenal.1998.275.2.F239. PMID 9691014.
- ^ Palmada M, Poppendieck S, Embark HM, van de Graaf SF, Boehmer C, Bindels RJ, Lang F (2005). "Requirement of PDZ domains for the stimulation of the epithelial Ca2+ channel TRPV5 by the NHE regulating factor NHERF2 and the serum and glucocorticoid inducible kinase SGK1". Cellular Physiology and Biochemistry. 15 (1–4): 175–182. doi:10.1159/000083650. hdl:2066/48079. PMID 15665527.
- ^ Jing H, Na T, Zhang W, Wu G, Liu C, Peng JB (Jan 2011). "Concerted actions of NHERF2 and WNK4 in regulating TRPV5". Biochemical and Biophysical Research Communications. 404 (4): 979–984. doi:10.1016/j.bbrc.2010.12.095. PMC 3031669. PMID 21187068.
- ^ a b c Palmada M, Dieter M, Boehmer C, Waldegger S, Lang F (Sep 2004). "Serum and glucocorticoid inducible kinases functionally regulate ClC-2 channels". Biochemical and Biophysical Research Communications. 321 (4): 1001–1006. doi:10.1016/j.bbrc.2004.07.064. PMID 15358127.
- ^ Boehmer C, Wilhelm V, Palmada M, Wallisch S, Henke G, Brinkmeier H, Cohen P, Pieske B, Lang F (Mar 2003). "Serum and glucocorticoid inducible kinases in the regulation of the cardiac sodium channel SCN5A". Cardiovascular Research. 57 (4): 1079–1084. doi:10.1016/s0008-6363(02)00837-4. PMID 12650886.
- ^ a b c d e f Lang F, Stournaras C (2013). "Serum and glucocorticoid inducible kinase, metabolic syndrome, inflammation, and tumor growth". Hormones. 12 (2): 160–171. doi:10.14310/horm.2002.1401. PMID 23933686.
- ^ Takumi T, Ohkubo H, Nakanishi S (Nov 1988). "Cloning of a membrane protein that induces a slow voltage-gated potassium current". Science. 242 (4881): 1042–1045. Bibcode:1988Sci...242.1042T. doi:10.1126/science.3194754. PMID 3194754.
- ^ a b c Gamper N, Fillon S, Huber SM, Feng Y, Kobayashi T, Cohen P, Lang F (Feb 2002). "IGF-1 up-regulates K+ channels via PI3-kinase, PDK1 and SGK1". Pflügers Archiv. 443 (4): 625–634. doi:10.1007/s00424-001-0741-5. PMID 11907830. S2CID 85469972.
- ^ a b c Strutz-Seebohm N, Seebohm G, Shumilina E, Mack AF, Wagner HJ, Lampert A, Grahammer F, Henke G, Just L, Skutella T, Hollmann M, Lang F (Jun 2005). "Glucocorticoid adrenal steroids and glucocorticoid-inducible kinase isoforms in the regulation of GluR6 expression". The Journal of Physiology. 565 (Pt 2): 391–401. doi:10.1113/jphysiol.2004.079624. PMC 1464533. PMID 15774535.
- ^ a b Boini KM, Hennige AM, Huang DY, Friedrich B, Palmada M, Boehmer C, Grahammer F, Artunc F, Ullrich S, Avram D, Osswald H, Wulff P, Kuhl D, Vallon V, Häring HU, Lang F (Jul 2006). "Serum- and glucocorticoid-inducible kinase 1 mediates salt sensitivity of glucose tolerance". Diabetes. 55 (7): 2059–2066. doi:10.2337/db05-1038. PMID 16804076.
- ^ a b Shojaiefard M, Christie DL, Lang F (Sep 2005). "Stimulation of the creatine transporter SLC6A8 by the protein kinases SGK1 and SGK3". Biochemical and Biophysical Research Communications. 334 (3): 742–746. doi:10.1016/j.bbrc.2005.06.164. PMID 16036218.
- ^ a b c d e f g h i j k l m n o p q r s Lang F, Böhmer C, Palmada M, Seebohm G, Strutz-Seebohm N, Vallon V (Oct 2006). "(Patho)physiological significance of the serum- and glucocorticoid-inducible kinase isoforms". Physiological Reviews. 86 (4): 1151–1178. doi:10.1152/physrev.00050.2005. PMID 17015487.
- ^ a b Waldegger S, Barth P, Raber G, Lang F (Apr 1997). "Cloning and characterization of a putative human serine/threonine protein kinase transcriptionally modified during anisotonic and isotonic alterations of cell volume". Proceedings of the National Academy of Sciences of the United States of America. 94 (9): 4440–4445. Bibcode:1997PNAS...94.4440W. doi:10.1073/pnas.94.9.4440. PMC 20741. PMID 9114008.
- ^ Wulff P, Vallon V, Huang DY, Völkl H, Yu F, Richter K, Jansen M, Schlünz M, Klingel K, Loffing J, Kauselmann G, Bösl MR, Lang F, Kuhl D (Nov 2002). "Impaired renal Na(+) retention in the sgk1-knockout mouse". The Journal of Clinical Investigation. 110 (9): 1263–1268. doi:10.1172/jci15696. PMC 151609. PMID 12417564.
- ^ a b c Ma YL, Tsai MC, Hsu WL, Lee EH (2006). "SGK protein kinase facilitates the expression of long-term potentiation in hippocampal neurons". Learning & Memory. 13 (2): 114–118. doi:10.1101/lm.179206. PMID 16585788.
- ^ a b Anacker C, Cattaneo A, Musaelyan K, Zunszain PA, Horowitz M, Molteni R, Luoni A, Calabrese F, Tansey K, Gennarelli M, Thuret S, Price J, Uher R, Riva MA, Pariante CM (May 2013). "Role for the kinase SGK1 in stress, depression, and glucocorticoid effects on hippocampal neurogenesis". Proceedings of the National Academy of Sciences of the United States of America. 110 (21): 8708–8713. Bibcode:2013PNAS..110.8708A. doi:10.1073/pnas.1300886110. PMC 3666742. PMID 23650397.
- ^ Leong ML, Maiyar AC, Kim B, O'Keeffe BA, Firestone GL (Feb 2003). "Expression of the serum- and glucocorticoid-inducible protein kinase, Sgk, is a cell survival response to multiple types of environmental stress stimuli in mammary epithelial cells". The Journal of Biological Chemistry. 278 (8): 5871–5882. doi:10.1074/jbc.m211649200. PMID 12488318.
- ^ Wald H, Garty H, Palmer LG, Popovtzer MM (Aug 1998). "Differential regulation of ROMK expression in kidney cortex and medulla by aldosterone and potassium". The American Journal of Physiology. 275 (2 Pt 2): F303–F313. doi:10.1152/ajprenal.1998.275.2.F239. PMID 9691014.
- ^ Faresse N, Lagnaz D, Debonneville A, Ismailji A, Maillard M, Fejes-Toth G, Náray-Fejes-Tóth A, Staub O (Apr 2012). "Inducible kidney-specific Sgk1 knockout mice show a salt-losing phenotype". American Journal of Physiology. Renal Physiology. 302 (8): F977–F985. doi:10.1152/ajprenal.00535.2011. PMID 22301619.
- ^ Huang DY, Boini KM, Friedrich B, Metzger M, Just L, Osswald H, Wulff P, Kuhl D, Vallon V, Lang F (Apr 2006). "Blunted hypertensive effect of combined fructose and high-salt diet in gene-targeted mice lacking functional serum- and glucocorticoid-inducible kinase SGK1". American Journal of Physiology. Regulatory, Integrative and Comparative Physiology. 290 (4): R935–R944. doi:10.1152/ajpregu.00382.2005. PMID 16284089.
- ^ Coric T, Hernandez N, Alvarez de la Rosa D, Shao D, Wang T, Canessa CM (Apr 2004). "Expression of ENaC and serum- and glucocorticoid-induced kinase 1 in the rat intestinal epithelium". American Journal of Physiology. Gastrointestinal and Liver Physiology. 286 (4): G663–G670. doi:10.1152/ajpgi.00364.2003. PMID 14630642. S2CID 23627333.
- ^ Das S, Aiba T, Rosenberg M, Hessler K, Xiao C, Quintero PA, Ottaviano FG, Knight AC, Graham EL, Boström P, Morissette MR, del Monte F, Begley MJ, Cantley LC, Ellinor PT, Tomaselli GF, Rosenzweig A (Oct 2012). "Pathological role of serum- and glucocorticoid-regulated kinase 1 in adverse ventricular remodeling". Circulation. 126 (18): 2208–2219. doi:10.1161/circulationaha.112.115592. PMC 3484211. PMID 23019294.
- ^ Busjahn A, Seebohm G, Maier G, Toliat MR, Nürnberg P, Aydin A, Luft FC, Lang F (2004). "Association of the serum and glucocorticoid regulated kinase (sgk1) gene with QT interval". Cellular Physiology and Biochemistry. 14 (3): 135–142. doi:10.1159/000078105. PMID 15107590. S2CID 25348868.
- ^ a b Seebohm G, Strutz-Seebohm N, Birkin R, Dell G, Bucci C, Spinosa MR, Baltaev R, Mack AF, Korniychuk G, Choudhury A, Marks D, Pagano RE, Attali B, Pfeufer A, Kass RS, Sanguinetti MC, Tavare JM, Lang F (Mar 2007). "Regulation of endocytic recycling of KCNQ1/KCNE1 potassium channels". Circulation Research. 100 (5): 686–692. doi:10.1161/01.RES.0000260250.83824.8f. PMID 17293474.
- ^ Seebohm G, Strutz-Seebohm N, Ureche ON, Henrion U, Baltaev R, Mack AF, Korniychuk G, Steinke K, Tapken D, Pfeufer A, Kääb S, Bucci C, Attali B, Merot J, Tavare JM, Hoppe UC, Sanguinetti MC, Lang F (Dec 2008). "Long QT syndrome-associated mutations in KCNQ1 and KCNE1 subunits disrupt normal endosomal recycling of IKs channels". Circulation Research. 103 (12): 1451–1457. doi:10.1161/CIRCRESAHA.108.177360. PMID 19008479.
- ^ Pellegrini-Giampietro DE, Bennett MV, Zukin RS (Sep 1992). "Are Ca(2+)-permeable kainate/AMPA receptors more abundant in immature brain?". Neuroscience Letters. 144 (1–2): 65–69. doi:10.1016/0304-3940(92)90717-L. PMID 1331916. S2CID 23774762.
- ^ Rangone H, Poizat G, Troncoso J, Ross CA, MacDonald ME, Saudou F, Humbert S (Jan 2004). "The serum- and glucocorticoid-induced kinase SGK inhibits mutant huntingtin-induced toxicity by phosphorylating serine 421 of huntingtin". The European Journal of Neuroscience. 19 (2): 273–279. doi:10.1111/j.0953-816x.2003.03131.x. PMID 14725621. S2CID 31016239.
- ^ Roux JC, Zala D, Panayotis N, Borges-Correia A, Saudou F, Villard L (Feb 2012). "Modification of Mecp2 dosage alters axonal transport through the Huntingtin/Hap1 pathway". Neurobiology of Disease. 45 (2): 786–795. doi:10.1016/j.nbd.2011.11.002. PMID 22127389. S2CID 24617851.
- ^ Nuber UA, Kriaucionis S, Roloff TC, Guy J, Selfridge J, Steinhoff C, Schulz R, Lipkowitz B, Ropers HH, Holmes MC, Bird A (Aug 2005). "Up-regulation of glucocorticoid-regulated genes in a mouse model of Rett syndrome". Human Molecular Genetics. 14 (15): 2247–2256. doi:10.1093/hmg/ddi229. PMID 16002417.
- ^ Maiyar AC, Leong ML, Firestone GL (Mar 2003). "Importin-alpha mediates the regulated nuclear targeting of serum- and glucocorticoid-inducible protein kinase (Sgk) by recognition of a nuclear localization signal in the kinase central domain". Molecular Biology of the Cell. 14 (3): 1221–39. doi:10.1091/mbc.E02-03-0170. PMC 151592. PMID 12631736.
- ^ Hayashi M, Tapping RI, Chao TH, Lo JF, King CC, Yang Y, Lee JD (Mar 2001). "BMK1 mediates growth factor-induced cell proliferation through direct cellular activation of serum and glucocorticoid-inducible kinase". The Journal of Biological Chemistry. 276 (12): 8631–4. doi:10.1074/jbc.C000838200. PMID 11254654.
- ^ Asher C, Sinha I, Garty H (May 2003). "Characterization of the interactions between Nedd4-2, ENaC, and sgk-1 using surface plasmon resonance". Biochimica et Biophysica Acta (BBA) - Biomembranes. 1612 (1): 59–64. doi:10.1016/s0005-2736(03)00083-x. PMID 12729930.
- ^ Snyder PM, Olson DR, Thomas BC (Jan 2002). "Serum and glucocorticoid-regulated kinase modulates Nedd4-2-mediated inhibition of the epithelial Na+ channel". The Journal of Biological Chemistry. 277 (1): 5–8. doi:10.1074/jbc.C100623200. PMID 11696533.
- ^ a b Chun J, Kwon T, Lee E, Suh PG, Choi EJ, Sun Kang S (Oct 2002). "The Na(+)/H(+) exchanger regulatory factor 2 mediates phosphorylation of serum- and glucocorticoid-induced protein kinase 1 by 3-phosphoinositide-dependent protein kinase 1". Biochemical and Biophysical Research Communications. 298 (2): 207–15. doi:10.1016/s0006-291x(02)02428-2. PMID 12387817.
- ^ Park J, Leong ML, Buse P, Maiyar AC, Firestone GL, Hemmings BA (Jun 1999). "Serum and glucocorticoid-inducible kinase (SGK) is a target of the PI 3-kinase-stimulated signaling pathway". The EMBO Journal. 18 (11): 3024–33. doi:10.1093/emboj/18.11.3024. PMC 1171384. PMID 10357815.
- ^ Yun CC, Chen Y, Lang F (Mar 2002). "Glucocorticoid activation of Na(+)/H(+) exchanger isoform 3 revisited. The roles of SGK1 and NHERF2". The Journal of Biological Chemistry. 277 (10): 7676–83. doi:10.1074/jbc.M107768200. PMID 11751930.