Human glycogen synthase kinase-3 (GSK-3) is a multisubstrate, proline-directed kinase that
phosphorylates tau, beta-amyloid and neurofilaments. Stimulation of glycogen synthesis is one of the major physiological responses modulated by insulin. Studies have focussed on the possible role of glycogen synthase
kinase-3 (GSK-3) in the activation of glycogen synthase (GS) - a key enzyme of
glycogen metabolism.
NCBI Summary:
The protein encoded by this gene is a serine-threonine kinase belonging to the glycogen synthase kinase subfamily. It is a negative regulator of glucose homeostasis and is involved in energy metabolism, inflammation, ER-stress, mitochondrial dysfunction, and apoptotic pathways. Defects in this gene have been associated with Parkinson disease and Alzheimer disease. [provided by RefSeq, Aug 2017]
GSK-3β protects fetal oocytes from premature death via modulating TAp63 expression in mice. Wen J et al. (2019) Female mammals have a limited reproductive lifespan determined by the size of the primordial follicle pool established perinatally. Over two thirds of fetal oocytes are abolished via programmed cell death during early folliculogenesis. However, the underlying mechanisms governing fetal oocyte attrition remain largely elusive. Here, we demonstrate that glycogen synthase kinase-3 beta (GSK-3β) is indispensable for fetal oocyte maintenance during meiotic prophase I in mice. In vitro inhibition of GSK-3β activity or in vivo conditional deletion of Gsk-3β in the germline led to a dramatic loss of fetal oocytes via apoptosis, which subsequently resulted in a reduced capacity of the primordial follicle pool. Inhibition of GSK-3β also impeded meiotic progression in fetal oocytes and led to a deficiency in DNA double-strand break (DSB) repair associated with premature upregulation of Tap63, the major genome guardian of the female germline, following GSK-3β inhibition in fetal ovaries. Mechanistically, we demonstrated that aberrant nuclear translocation of β-catenin was responsible for the abnormal expression of TAp63 and global fetal oocyte attrition following GSK-3β inhibition. In summary, GSK-3β was essential for sustaining fetal oocyte survival and folliculogenesis via fine-tuning the cytoplasmic-nuclear translocation of β-catenin, which in turn modulates timely TAp63 expression during meiotic prophase I in mice. Our study provides a perspective on the physiological regulatory role of DNA damage checkpoint signaling in fetal oocyte guardianship and female fertility.//////////////////
Convergence of 3',5'-Cyclic Adenosine 5'-Monophosphate/Protein Kinase A and Glycogen Synthase Kinase-3{beta}/{beta}-Catenin Signaling in Corpus Luteum Progesterone Synthesis. Roy L et al. Progesterone secretion by the steroidogenic cells of the corpus luteum (CL) is essential for reproduction. Progesterone synthesis is under the control of LH, but the exact mechanism of this regulation is unknown. It is established that LH stimulates the LH receptor/choriogonadotropin receptor, a G-protein coupled receptor, to increase cAMP and activate cAMP-dependent protein kinase A (PKA). In the present study, we tested the hypothesis that cAMP/PKA-dependent regulation of the Wnt pathway components glycogen synthase kinase (GSK)-3beta and beta-catenin contributes to LH-dependent steroidogenesis in luteal cells. We observed that LH via a cAMP/PKA-dependent mechanism stimulated the phosphorylation of GSK3beta at N-terminal Ser9 causing its inactivation and resulted in the accumulation of beta-catenin. Overexpression of N-terminal truncated beta-catenin (Delta90 beta-catenin), which lacks the phosphorylation sites responsible for its destruction, significantly augmented LH-stimulated progesterone secretion. In contrast, overexpression of a constitutively active mutant of GSK3beta (GSK-S9A) reduced beta-catenin levels and inhibited LH-stimulated steroidogenesis. Chromatin immunoprecipitation assays demonstrated the association of beta-catenin with the proximal promoter of the StAR gene, a gene that expresses the steroidogenic acute regulatory protein, which is a cholesterol transport protein that controls a rate-limiting step in steroidogenesis. Collectively these data suggest that cAMP/PKA regulation of GSK3beta/beta-catenin signaling may contribute to the acute increase in progesterone production in response to LH.
Glycogen Synthase Kinase 3B in bovine oocytes and granulosa cells: possible involvement in meiosis during in vitro maturation. Uzbekova S et al. Glycogen Synthase Kinase 3 (GSK3) regulates cellular metabolism and cell cycle via different signalling pathways. In response to insulin and growth factors GSK3 is Serine-phosphorylated and inactivated. We analysed GSK3B expression and activation in bovine cumulus cells and oocytes at different meiotic stages in vitro in parallel with MAP kinases ERK (MAPK3/MAPK1) and p38 (MAPK14). GSK3B localised to cytoplasm in granulosa cells and in oocytes throughout folliculogenesis. In mature metaphase-II oocytes, GSK3B was concentrated to the region of midzone between the oocyte and the first polar body, as well as active phospho-Thr Aurora A kinase (AURKA). During in vitro maturation (IVM), in oocytes, phospho-Ser9-GSK3B level increased as well as phospho-MAPK3/MAPK1, while phospho-MAPK14 decreased. In cumulus cells, phospho-MAPK14 increased upon GVBD/metaphase-I and then fall down during transition to metaphase-II. Administration of inhibitors of GSK3 activity (lithium chloride or BIO) rapidly increased phospho-Ser9-GSK3B, and led to transient decrease of phospho-MAPK3/MAPK1 and to durable enhancing of phospho-MAPK14 in granulosa primary cell culture. GSK3 inhibitors during IVM diminished cumulus expansion and delayed meiotic progression of oocytes. In cumulus, phospho-MAPK14 level was significantly higher in the presence of GSK3 inhibitors, comparing to control, through the time of metaphase-I / II transition. In treated oocytes, phospho- Ser9-GSK3B was increased and phospho-MAPK3/MAPK1 was decreased before GVBD and oocytes were mainly arrested at metaphase-I. Therefore, GSK3B might regulate oocyte meiosis, notably metaphase-I / II transition being the part of MAPK3/1 and MAPK14 pathways in oocytes and cumulus cells. GSK3B might be also involved in the local activation of AURKA that controls this transition.
Lau KF et al reported that Northern
analysis demonstrated that GSK-3alpha is encoded by a 2.6-kb mRNA and GSK-3beta by 8.3- and
2.8-kb mRNAs. The two GSK-3beta mRNA species were variably expressed in different tissues.
Northern and quantitative polymerase chain reaction demonstrated that both GSK-3alpha and GSK-3beta
mRNA were prominently expressed in testis, thymus, prostate and ovary but were low in adult lung and
kidney. Western blot analysis showed that the 51-kDa GSK-3alpha protein was highly expressed in lung,
ovary, kidney and testis, whereas the 46-kDa GSK-3beta protein was highly expressed in lung, kidney
and brain. The differential expression of GSK-3alpha and GSK-3beta mRNA and proteins and the lack
of relationship between transcription and translation in some tissues indicate that GSK-3alpha and
GSK-3beta are subject to different means of regulation.
The stabilization of beta-catenin leads to impaired primordial germ cell development via aberrant cell cycle progression. Kimura T et al. Primordial germ cells (PGCs) are germ cell precursors that are committed to sperm or oocytes. Dramatic proliferation during PGC development determines the number of founder spermatogonia and oocytes. Although specified to a germ lineage, PGCs produce pluripotent embryonic germ (EG) cells in vitro and testicular teratomas in vivo. Wnt/beta-catenin signaling regulates pluripotency and differentiation in various stem cell systems, and dysregulation of this signaling causes various human cancers. Here, we examined the role of Wnt/beta-catenin signaling in PGC development. In normal PGC development, Wnt/beta-catenin signaling is suppressed by the GSK3beta-mediated active degradation of beta-catenin and the low expression of canonical Wnt molecules. The effects of aberrant activation of Wnt/beta-catenin signaling in PGCs were analyzed using mice carrying a deletion of the exon that encodes the GSK3beta phosphorylation sites in the beta-catenin locus. Despite the potential activity of Wnt/beta-catenin signaling in stem cell maintenance and carcinogenesis in various cell lineages, teratomas were not induced in the mice expressing the nuclear-localized beta-catenin in PGCs. Instead, the mutant mice showed germ cell deficiency caused by the delayed cell cycle progression of the proliferative phase PGCs. Our results show that the suppression of Wnt/beta-catenin signaling is a prerequisite for the normal development of PGCs.
Antibody Microarray Analyses of Signal Transduction Protein Expression and Phosphorylation during Porcine Oocyte Maturation. Pelech S et al. Kinex antibody microarray analyses was used to investigate the regulation of 188 protein kinases, 24 protein phosphatases, and 170 other regulatory proteins during meiotic maturation of immature germinal vesicle (GV+) pig oocytes to maturing oocytes that had completed meiosis I (MI), and fully mature oocytes arrested at metaphase of meiosis II (MII). Increases in apparent protein levels of protein kinases accounted for most of the detected changes during the GV to MI transition, whereas reduced protein kinase levels and increased protein phosphorylation characterized the MI to MII transition. During the MI to MII period, many of the MI-associated increased levels of the proteins and phosphosites were completely or partially reversed. The regulation of these proteins were also examined in parallel during the meiotic maturation of bovine, frog, and sea star oocytes with the Kinex antibody microarray. Western blotting analyses confirmed altered expression levels of Bub1A, IRAK4, MST2, PP4C, and Rsk2, and the phosphorylation site changes in the kinases Erk5 (T218 + Y220), FAK (S722), GSK3-beta (Y216), MEK1 (S217 + S221) and PKR1 (T451), and nucleophosmin/B23 (S4) during pig oocyte maturation.
Expression regulated by
LH, Growth Factors/ cytokines
Comment
Luteinizing Hormone Stimulates Mammalian Target of Rapamycin Signaling in Bovine Luteal Cells via Pathways Independent of AKT and Mitogen-Activated Protein Kinase: Modulation of Glycogen Synthase Kinase 3 and AMP-Activated Protein Kinase. Hou X et al. LH stimulates the production of cAMP in luteal cells, which leads to the production of progesterone, a hormone critical for the maintenance of pregnancy. The mammalian target of rapamycin (MTOR) signaling cascade has recently been examined in ovarian follicles where it regulates granulosa cell proliferation and differentiation. This study examined the actions of LH on the regulation and possible role of the MTOR signaling pathway in primary cultures of bovine corpus luteum cells. Herein, we demonstrate that activation of the LH receptor stimulates the phosphorylation of the MTOR substrates ribosomal protein S6 kinase 1 (S6K1) and eukaryotic translation initiation factor 4E binding protein 1. The actions of LH were mimicked by forskolin and 8-bromo-cAMP. LH did not increase AKT or MAPK1/3 phosphorylation. Studies with pathway-specific inhibitors demonstrated that the MAPK kinase 1 (MAP2K1)/MAPK or phosphatidylinositol 3-kinase/AKT signaling pathways were not required for LH-stimulated MTOR/S6K1 activity. However, LH decreased the activity of glycogen synthase kinase 3B (GSK3B) and AMP-activated protein kinase (AMPK). The actions of LH on MTOR/S6K1 were mimicked by agents that modulated GSK3B and AMPK activity. The ability of LH to stimulate progesterone secretion was not prevented by rapamycin, a MTOR inhibitor. In contrast, activation of AMPK inhibited LH-stimulated MTOR/S6K1 signaling and progesterone secretion. In summary, the LH receptor stimulates a unique series of intracellular signals to activate MTOR/S6K1 signaling. Furthermore, LH-directed changes in AMPK and GSK3B phosphorylation appear to exert a greater impact on progesterone synthesis in the corpus luteum than rapamycin-sensitive MTOR-mediated events.
Phosphorylation and inactivation of glycogen synthase kinase-3 by soluble kit ligand in mouse oocytes during early follicular development. Liu L et al. Communication between mammalian oocytes and their surrounding granulosa cells through the Kit-Kit ligand (KL, or stem cell factor, SCF) system has been shown to be crucial for follicular development. Our previous studies (Reddy et al. 2005, Liu et al. 2006) have indicated that the intra-oocyte KL-Kit-PI3 kinase (PI3K)-Akt-Foxo3a cascade may play an important role in follicular activation and early development. In the present study, using in situ hybridization and in vitro culture of growing oocytes from 8-day-old postnatal mice, we have demonstrated that another Akt substrate, glycogen synthase kinase-3 (GSK-3), is expressed in growing oocytes. Also, treatment of cultured mouse oocytes with soluble KL not only leads to increased Akt kinase activity in the oocytes, which can phosphorylate recombinant GSK-3 in vitro, but also leads to phosphorylation of oocyte GSK-3alpha and GSK-3beta, which can result in the inactivation of GSK-3 function in oocytes. In addition, we have shown that the regulation of GSK-3alpha and GSK-3beta in cultured oocytes by soluble KL is accomplished through PI3K, since the PI3K-specific inhibitor LY294002 completely abolished the KL-induced phosphorylation of GSK-3alpha and GSK-3beta. Moreover, blockage of the Kit signaling pathway by a Kit function-blocking antibody, ACK2, resulted in reduced phosphorylation of GSK-3. Taken together, our data suggest that the cascade from granulosa cell-derived KL to Kit-PI3K-Akt-GSK-3 in oocytes may take part in regulation of oocyte growth and early ovarian follicular development.
Ovarian localization
Oocyte, Cumulus, Granulosa
Comment
Luteinizing hormone receptor activation in ovarian granulosa cells promotes protein kinase A-dependent dephosphorylation of microtubule-associated protein 2D. Flynn MP et al. The actions of LH to induce ovulation and luteinization of preovulatory follicles are mediated principally by activation of cAMP-dependent protein kinase (PKA) in granulosa cells. PKA activity is targeted to specific locations in many cells by A kinase-anchoring proteins (AKAPs). We previously showed that FSH induces expression of microtubule-associated protein (MAP) 2D, an 80-kDa AKAP, in rat granulosa cells, and that MAP2D coimmunoprecipitates with PKA-regulatory subunits in these cells. Here we report a rapid and targeted dephosphorylation of MAP2D at Thr256/Thr259 after treatment with human chorionic gonadotropin, an LH receptor agonist. This event is mimicked by treatment with forskolin or a cAMP analog and is blocked by the PKA inhibitor myristoylated-PKI, indicating a role for cAMP and PKA signaling in phosphoregulation of granulosa cell MAP2D. Furthermore, we show that Thr256/Thr259 dephosphorylation is blocked by the protein phosphatase 2A (PP2A) inhibitor, okadaic acid, and demonstrate interactions between MAP2D and PP2A by coimmunoprecipitation and microcystin-agarose pull-down. We also show that MAP2D interacts with glycogen synthase kinase (GSK) 3beta and is phosphorylated at Thr256/Thr259 by this kinase in the basal state. Increased phosphorylation of GSK3beta at Ser9 and the PP2A B56delta subunit at Ser566 is observed after treatment with human chorionic gonadotropin and appears to result in LH receptor-mediated inhibition of GSK3beta and activation of PP2A, respectively. Taken together, these results show that the phosphorylation status of the AKAP MAP2D is acutely regulated by LH receptor-mediated modulation of kinase and phosphatase activities via PKA.
Glycogen Synthase Kinase 3B in bovine oocytes and granulosa cells: possible involvement in meiosis during in vitro maturation. Uzbekova S et al. Glycogen Synthase Kinase 3 (GSK3) regulates cellular metabolism and cell cycle via different signalling pathways. In response to insulin and growth factors GSK3 is Serine-phosphorylated and inactivated. We analysed GSK3B expression and activation in bovine cumulus cells and oocytes at different meiotic stages in vitro in parallel with MAP kinases ERK (MAPK3/MAPK1) and p38 (MAPK14). GSK3B localised to cytoplasm in granulosa cells and in oocytes throughout folliculogenesis. In mature metaphase-II oocytes, GSK3B was concentrated to the region of midzone between the oocyte and the first polar body, as well as active phospho-Thr Aurora A kinase (AURKA). During in vitro maturation (IVM), in oocytes, phospho-Ser9-GSK3B level increased as well as phospho-MAPK3/MAPK1, while phospho-MAPK14 decreased. In cumulus cells, phospho-MAPK14 increased upon GVBD/metaphase-I and then fall down during transition to metaphase-II. Administration of inhibitors of GSK3 activity (lithium chloride or BIO) rapidly increased phospho-Ser9-GSK3B, and led to transient decrease of phospho-MAPK3/MAPK1 and to durable enhancing of phospho-MAPK14 in granulosa primary cell culture. GSK3 inhibitors during IVM diminished cumulus expansion and delayed meiotic progression of oocytes. In cumulus, phospho-MAPK14 level was significantly higher in the presence of GSK3 inhibitors, comparing to control, through the time of metaphase-I / II transition. In treated oocytes, phospho- Ser9-GSK3B was increased and phospho-MAPK3/MAPK1 was decreased before GVBD and oocytes were mainly arrested at metaphase-I. Therefore, GSK3B might regulate oocyte meiosis, notably metaphase-I / II transition being the part of MAPK3/1 and MAPK14 pathways in oocytes and cumulus cells. GSK3B might be also involved in the local activation of AURKA that controls this transition.
Follicle stages
Comment
Phenotypes
PCO (polycystic ovarian syndrome)
Mutations
3 mutations
Species: mouse
Mutation name: None
type: targeted overexpression fertility: subfertile Comment: The stabilization of beta-catenin leads to impaired primordial germ cell development via aberrant cell cycle progression. Kimura T et al. Primordial germ cells (PGCs) are germ cell precursors that are committed to sperm or oocytes. Dramatic proliferation during PGC development determines the number of founder spermatogonia and oocytes. Although specified to a germ lineage, PGCs produce pluripotent embryonic germ (EG) cells in vitro and testicular teratomas in vivo. Wnt/beta-catenin signaling regulates pluripotency and differentiation in various stem cell systems, and dysregulation of this signaling causes various human cancers. Here, we examined the role of Wnt/beta-catenin signaling in PGC development. In normal PGC development, Wnt/beta-catenin signaling is suppressed by the GSK3beta-mediated active degradation of beta-catenin and the low expression of canonical Wnt molecules. The effects of aberrant activation of Wnt/beta-catenin signaling in PGCs were analyzed using mice carrying a deletion of the exon that encodes the GSK3beta phosphorylation sites in the beta-catenin locus. Despite the potential activity of Wnt/beta-catenin signaling in stem cell maintenance and carcinogenesis in various cell lineages, teratomas were not induced in the mice expressing the nuclear-localized beta-catenin in PGCs. Instead, the mutant mice showed germ cell deficiency caused by the delayed cell cycle progression of the proliferative phase PGCs. Our results show that the suppression of Wnt/beta-catenin signaling is a prerequisite for the normal development of PGCs.
Species: human
Mutation name: None
type: naturally occurring fertility: subfertile Comment: Preliminary evidence of glycogen synthase kinase 3 beta as a genetic determinant of polycystic ovary syndrome. Goodarzi MO et al. In this study of 352 women with polycystic ovary syndrome (PCOS) and 289 control women, haplotypes spanning the gene for glycogen synthase kinase 3beta (GSK3B) were constructed on the basis of nine single-nucleotide polymorphisms in white and black subjects separately. In each racial group, we observed that a specific, although different, GSK3B haplotype was associated with increased frequency of PCOS, suggesting that GSK3beta contributes to the pathophysiology and inherited basis of PCOS.
Species: mouse
Mutation name: type: null mutation fertility: fertile Comment: Loss of Glycogen Synthase Kinase 3 Isoforms During Murine Oocyte Growth Induces Offspring Cardiac Dysfunction. Monteiro da Rocha A et al. (2015) Glycogen synthase kinase-3 (GSK3) is a constitutively active serine threonine kinase with i) two isoforms (GSK3A and GSK3B) having unique and overlapping functions, ii) multiple molecular intracellular mechanisms involving phosphorylation of diverse substrates, and iii) implications in pathogenesis of many diseases. Insulin causes phosphorylation and inactivation of GSK3 and mammalian oocytes have a functional insulin signaling pathway whereby prolonged elevated insulin during follicle/oocyte development causes GSK3 hyperphosphorylation, reduced GSK3 activity, and altered oocyte chromatin remodeling. Periconceptional diabetes and chronic hyperinsulinemia are associated with congenital malformations and onset of adult diseases of cardiovascular origin. Objectives were to produce transgenic mice with individual or concomitant loss of GSK3A and/or GSK3B and investigate the in vivo role of oocyte GSK3 on fertility, fetal development, and offspring health. Wild type males bred to females with individual or concomitant loss of oocyte GSK3 isoforms did not have reduced fertility. However, concomitant loss of GSK3A and GSK3B in the oocyte significantly increased neonatal death rate due to congestive heart failure secondary to ventricular hyperplasia. Individual loss of oocyte GSK3A or GSK3B did not induce this lethal phenotype. In conclusion, absence of oocyte GSK3 in the periconceptional period does not alter fertility yet causes offspring cardiac hyperplasia, cardiovascular defects, and significant neonatal death. These results support a developmental mechanism by which periconceptional hyperinsulinemia associated with maternal metabolic syndrome, obesity, and/or diabetes can act on the oocyte and impact offspring cardiovascular development, function, and congenital heart malformation.//////////////////