56-542: Glycogen synthase kinase 3 ( GSK-3 ) is a serine/threonine protein kinase that mediates the addition of phosphate molecules onto serine and threonine amino acid residues. First discovered in 1980 as a regulatory kinase for its namesake, glycogen synthase (GS), GSK-3 has since been identified as a protein kinase for over 100 different proteins in a variety of different pathways. In mammals, including humans, GSK-3 exists in two isozymes encoded by two homologous genes GSK-3α ( GSK3A ) and GSK-3β ( GSK3B ). GSK-3 has been
112-489: A decrease in glycogen synthesis in the liver and muscles, along with increased blood glucose or hyperglycemia. This is why GSK-3β is associated with the pathogenesis and progression of many diseases, such as diabetes , obesity , cancer , and Alzheimer's disease. It is active in resting cells and is inhibited by several hormones such as insulin , endothelial growth factor , and platelet-derived growth factor . Insulin indirectly inactivates GSK3 via downstream phosphorylation of
168-679: A dose dependent manner. A fourfold increase in the liver glycogen level with the use of the highest dose of famotidine (4.4 mg/kg) was observed. Also, famotidine has been shown to decrease serum glucose levels 30, and 60 minutes after oral glucose load in healthy individuals. Curcumin, which Is a constituent of turmeric spice, has flavoring and coloring properties. It has two symmetrical forms: enol (the most abundant forms) and ketone. Curcumin has wide pharmacological activities: anti-inflammatory, anti-microbial, hypoglycemic, anti-oxidant, and wound healing effects. In animal models with Alzheimer disease, it has anti-destructive effect of beta amyloid in
224-447: A dose-dependent manner with a reduction in plasma glucose. Anti-obesity effects of naproxen and cromolyn: Both drugs showed significant anti-obesity effects as they reduce body weight, resistin, and glucose levels in a dose-dependent manner. They were also found to elevate adiponectin , insulin, and C-peptide levels in a dose-dependent manner. Famotidine is a specific, long-acting H2 antagonist that decreases gastric acid secretion. It
280-686: A high degree of amino acid homology. GSK3B is involved in energy metabolism, neuronal cell development, and body pattern formation. It might be a new therapeutic target for ischemic stroke. Homozygous disruption of the Gsk3b locus in mice results in embryonic lethality during mid-gestation. This lethality phenotype could be rescued by inhibition of tumor necrosis factor . Two SNPs at this gene, rs334558 (-50T/C) and rs3755557 (-1727A/T), are associated with efficacy of lithium treatment in bipolar disorder . Pharmacological inhibition of ERK1/2 restores GSK-3 beta activity and protein synthesis levels in
336-432: A key factor in tumorigenesis in some cancers. Supporting this claim, GSK-3 inhibitors have been shown to induce apoptosis in glioma and pancreatic cancer cells. GSK-3 also seems to be responsible for NFκB aberrant activity in pediatric acute lymphoblastic leukemia and pancreatic cancer cells. In renal cancer cells, GSK-3 inhibitors induce cell cycle arrest, differentiation of the malignant cells, and autophagy. In contrast to
392-405: A medium effect size for negative and total symptoms of schizophrenia. There also is evidence that L ‐serine could acquire a therapeutic role in diabetes. D -Serine is being studied in rodents as a potential treatment for schizophrenia. D -Serine also has been described as a potential biomarker for early Alzheimer's disease (AD) diagnosis, due to a relatively high concentration of it in
448-414: A neuromodulator by coactivating NMDA receptors , making them able to open if they then also bind glutamate . D -serine is a potent agonist at the glycine site (NR1) of canonical diheteromeric NMDA receptors . For the receptor to open, glutamate and either glycine or D -serine must bind to it; in addition a pore blocker must not be bound (e.g. Mg or Zn ). Some research has shown that D -serine
504-471: A non-essential amino acid has come to be considered as conditional, since vertebrates such as humans cannot always synthesize optimal quantities over entire lifespans. Safety of L -serine has been demonstrated in an FDA-approved human phase I clinical trial with Amyotrophic Lateral Sclerosis, ALS , patients (ClinicalTrials.gov identifier: NCT01835782), but treatment of ALS symptoms has yet to be shown. A 2011 meta-analysis found adjunctive sarcosine to have
560-446: A patient registry was established by the noncommercial International Working Group on Neurotransmitter Related Disorders (iNTD). Besides disruption of serine biosynthesis, its transport may also become disrupted. One example is spastic tetraplegia, thin corpus callosum, and progressive microcephaly , a disease caused by mutations that affect the function of the neutral amino acid transporter A . The classification of L -serine as
616-421: A serine or threonine residue on its target substrate. A positively charged pocket adjacent to the active site binds a "priming" phosphate group attached to a serine or threonine four residues C-terminal of the target phosphorylation site. The active site, at residues 181, 200, 97, and 85, binds the terminal phosphate of ATP and transfers it to the target location on the substrate (see figure 1). Glycogen synthase
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#1732776092098672-658: A significant decrease in blood glucose level and elevation of glycogen level in mice, and the IC50% of olanzapine were 91.0 nm, which is considered a potent inhibitor. The study also illustrates that sub-chronic use of olanzapine results in potent inhibition of GSK3. Pyrimidine analogues are antimetabolites that interfere with nucleic acid synthesis. Some of them have been shown to fit the ATP-binding pocket of GSK-3β to lower blood glucose levels and improve some neuronal diseases. Serine Serine (symbol Ser or S )
728-410: A significant role in the circadian clock. Elements of the circadian clock may be connected with predisposition to bipolar mood disorder. GSK-3 activity has been associated with both pathological features of Alzheimer's disease, namely the buildup of amyloid-β (Aβ) deposits and the formation of neurofibrillary tangles . GSK-3 is thought to directly promote Aβ production and to be tied to the process of
784-572: A silico docking technique. The concentration at which 50% of GK-3B would be inhibited by curcumin is 66.3 nM. Among its two forms, experimental and theoretical studies show that the enol form is the favored form due to its intra-molecular hydrogen bonding, and an NMR experiment show that enol form exist in a variety of solvents. Antipsychotic medications are increasingly used for schizophrenia , bipolar disorder, anxiety, and other psychiatric conditions Atypical antipsychotics are more commonly used than first generation antipsychotics because they decrease
840-417: A variable degree to treatment with L -serine, sometimes combined with glycine. Response to treatment is variable and the long-term and functional outcome is unknown. To provide a basis for improving the understanding of the epidemiology, genotype/phenotype correlation and outcome of these diseases their impact on the quality of life of patients, as well as for evaluating diagnostic and therapeutic strategies
896-522: A very faint musty aroma. D -Serine is sweet with an additional minor sour taste at medium and high concentrations. Serine deficiency disorders are rare defects in the biosynthesis of the amino acid L -serine. At present three disorders have been reported: These enzyme defects lead to severe neurological symptoms such as congenital microcephaly and severe psychomotor retardation and in addition, in patients with 3-phosphoglycerate dehydrogenase deficiency to intractable seizures. These symptoms respond to
952-539: Is a bi-lobar architecture with N-terminal and C-terminal , the N-terminal is responsible for ATP binding and C-terminal which is called as activation loop mediates the kinase activity, Tyrosine located at the C-terminal it essential for full GSK3 activity. In diabetes, GSK-3β inhibitors increase insulin sensitivity, glycogen synthesis, and glucose metabolism in skeletal muscles, and reduce obesity by affecting
1008-526: Is a more potent agonist at the NMDAR glycine site than glycine itself. However, D-serine has been shown to work as an antagonist/inverse co-agonist of t -NMDA receptors through the glycine binding site on the GluN3 subunit. D -serine was thought to exist only in bacteria until relatively recently; it was the second D amino acid discovered to naturally exist in humans, present as a signaling molecule in
1064-518: Is also integrally tied to pathways of cell proliferation and apoptosis. GSK-3 has been shown to phosphorylate Beta-catenin , thus targeting it for degradation. GSK-3 is therefore a part of the canonical Beta-catenin / Wnt pathway, which signals the cell to divide and proliferate. GSK-3 phosphorylates cyclins D and E, which are important for the transition from G1 to S phase, and causes their degradation. The transcription factors c-myc and c-fos (also S phase promoters ), which are primarily phosphorylated by
1120-528: Is an enzyme that in humans is encoded by the GSK3B gene . In mice, the enzyme is encoded by the Gsk3b gene. Abnormal regulation and expression of GSK-3 beta is associated with an increased susceptibility towards bipolar disorder . Glycogen synthase kinase-3 ( GSK-3 ) is a proline-directed serine-threonine kinase that was initially identified as a phosphorylating and an inactivating agent of glycogen synthase . Two isoforms, alpha ( GSK3A ) and beta, show
1176-488: Is an enzyme that is responsible in glycogen synthesis. It is activated by glucose 6-phosphate (G6P), and inhibited by glycogen synthase kinases ( GSK3 ). Those two mechanisms play an important role in glycogen metabolism. Phosphorylation of a protein by GSK-3 usually inhibits the activity of its downstream target. GSK-3 is active in a number of central intracellular signaling pathways, including cellular proliferation, migration, glucose regulation, and apoptosis. GSK-3
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#17327760920981232-399: Is an α- amino acid that is used in the biosynthesis of proteins. It contains an α- amino group (which is in the protonated − NH 3 form under biological conditions), a carboxyl group (which is in the deprotonated − COO form under biological conditions), and a side chain consisting of a hydroxymethyl group, classifying it as a polar amino acid. It can be synthesized in
1288-631: Is controversial, however, as some studies have shown that GSK-3β knockout mice are overly sensitized to apoptosis and die in the embryonic stage, while others have shown that overexpression of GSK-3 can induce apoptosis. Overall, GSK-3 appears to both promote and inhibit apoptosis, and this regulation varies depending on the specific molecular and cellular context. GSK-3 is also involved in nuclear transcriptional activator kappa B (NFκB) signaling pathway, Hedgehog signaling pathway, Notch signaling pathway, and epithelial-mesenchymal transition. Due to its importance across numerous cellular functions, GSK-3 activity
1344-432: Is evidence that lithium , which is used as a treatment for bipolar disorder , acts as a mood stabilizer by selectively inhibiting GSK-3. The mechanism through which GSK-3 inhibition may stabilize mood is not known, though it is suspected that the inhibition of GSK-3's ability to promote inflammation contributes to the therapeutic effect. Inhibition of GSK-3 also destabilises Rev-ErbA alpha transcriptional repressor, which has
1400-440: Is hydrolyzed to serine by phosphoserine phosphatase ( EC 3.1.3.3 ). In bacteria such as E. coli these enzymes are encoded by the genes serA (EC 1.1.1.95), serC (EC 2.6.1.52), and serB (EC 3.1.3.3). Serine hydroxymethyltransferase (SMHT) also catalyzes the biosynthesis of glycine (retro-aldol cleavage) from serine, transferring the resulting formalddehyde synthon to 5,6,7,8-tetrahydrofolate . However, that reaction
1456-434: Is reversible, and will convert excess glycine to serine. SHMT is a pyridoxal phosphate (PLP) dependent enzyme. Industrially, L -serine is produced from glycine and methanol catalyzed by hydroxymethyltransferase . Racemic serine can be prepared in the laboratory from methyl acrylate in several steps: Hydrogenation of serine gives the diol serinol : Serine is important in metabolism in that it participates in
1512-679: Is subject to tight regulation and is considered an "Ace" among kinases. The speed and efficacy of GSK-3 phosphorylation is regulated by several factors. Phosphorylation of certain GSK-3 residues can increase or decrease its ability to bind substrate. Phosphorylation at tyrosine-216 in GSK-3β or tyrosine-279 in GSK-3α enhances the enzymatic activity of GSK-3, while phosphorylation of autoinhibitory serine-9 in GSK-3β or serine-21 in GSK-3α significantly decreases active site availability (see figure). Further, GSK-3
1568-440: Is unusual among kinases in that it usually requires a "priming kinase" to first phosphorylate a substrate. A phosphorylated serine or threonine residue located four amino acids C-terminal to the target site of phosphorylation allows the substrate to bind a pocket of positive charge formed by arginine and lysine residues. Depending on the pathway in which it is being utilized, GSK-3 may be further regulated by cellular localization or
1624-512: Is used in the treatment of bipolar disorder was the first natural GSK-3 inhibitor discovered. It inhibits GSK-3 directly by competition with magnesium ions and indirectly by phosphorylation and auto-regulation of serine. Lithium has been found to have insulin-like effects on glucose metabolism, including stimulation of glycogen synthesis in fat cells, skin, and muscles, increasing glucose uptake, and activation of GS activity. In addition to inhibition of GSK-3, it also inhibits other enzymes involved in
1680-419: Is used in the treatment of peptic ulcer disease, GERD, and pathological hypersecretory conditions, like Zollinger–Ellison syndrome. (14,15) H2-receptor antagonists affect hormone metabolism, but their effect on glucose metabolism is not well established. (16) A study has revealed a glucose-lowering effect for famotidine. The study of famotidine binding to the enzyme has showed that famotidine can be docked within
1736-482: The adipogenesis process. GSK-3β is also over expressed in several types of cancers, like colorectal , ovarian , and prostate cancer . GSK-3β inhibitors also aid in the treatment of Alzheimer's disease , stroke , and mood disorders , including bipolar disorder . In vitro studies have shown the beneficial effects of GSK-3 inhibitors in lung cancer, ovarian cancer and neuroblastoma. Inhibitors of GSK-3 include: IC 50 =4-80nM: IC 50 =0.5-1.5μM: Lithium which
GSK-3 - Misplaced Pages Continue
1792-441: The biosynthesis of purines and pyrimidines . It is the precursor to several amino acids including glycine and cysteine , as well as tryptophan in bacteria. It is also the precursor to numerous other metabolites, including sphingolipids and folate , which is the principal donor of one-carbon fragments in biosynthesis. D -Serine, synthesized in neurons by serine racemase from L -serine (its enantiomer ), serves as
1848-1251: The cerebrospinal fluid of probable AD patients. D-serine, which is made in the brain, has been shown to work as an antagonist/inverse co-agonist of t -NMDA receptors mitigating neuron loss in an animal model of temporal lobe epilepsy . D -Serine has been theorized as a potential treatment for sensorineural hearing disorders such as hearing loss and tinnitus . GSK3B 1GNG , 1H8F , 1I09 , 1J1B , 1J1C , 1O6K , 1O6L , 1O9U , 1PYX , 1Q3D , 1Q3W , 1Q41 , 1Q4L , 1Q5K , 1R0E , 1UV5 , 2JDO , 2JDR , 2JLD , 2O5K , 2OW3 , 2UW9 , 2X39 , 2XH5 , 3CQU , 3CQW , 3DU8 , 3E87 , 3E88 , 3E8D , 3F7Z , 3F88 , 3GB2 , 3I4B , 3L1S , 3M1S , 3MV5 , 3OW4 , 3PUP , 3Q3B , 3QKK , 3SAY , 3SD0 , 3ZDI , 3ZRK , 3ZRL , 3ZRM , 4ACC , 4ACD , 4ACG , 4ACH , 4AFJ , 4B7T , 4DIT , 4EKK , 4IQ6 , 4J1R , 4J71 , 4NM0 , 4NM3 , 4NM5 , 4NM7 , 4PTC , 4PTE , 4PTG , 5F94 , 5F95 , 5HLP , 5HLN 2932 56637 ENSG00000082701 ENSMUSG00000022812 P49841 Q9WV60 NM_001146156 NM_002093 NM_001354596 NM_019827 NM_001347232 NP_001139628 NP_002084 NP_001341525 NP_001334161 NP_062801 Glycogen synthase kinase-3 beta , (GSK-3 beta) ,
1904-472: The hyperphosphorylation of tau proteins , which leads to the tangles. Due to these roles of GSK-3 in promoting Alzheimer's disease, GSK-3 inhibitors may have positive therapeutic effects on Alzheimer's patients and are currently in the early stages of testing. In a similar fashion, targeted inhibition of GSK-3 may have therapeutic effects on certain kinds of cancer. Though GSK-3 has been shown to promote apoptosis in some cases, it has also been reported to be
1960-744: The above neoplasms, high expression of inactive pGSK3β-S9 is found in skin, oral, and lung cancers, suggesting tumor suppressive effects of the enzyme in these cancers. In melanoma, the microRNA miR-769 inhibits GSK-3 activity during the tumor development process, also indicating tumor suppressive effects of GSK3. GSK-3 inhibitors have also shown promise in the treatment of T2DM. Though GSK-3 activity under diabetic conditions can differ radically across different tissue types, studies have shown that introducing competitive inhibitors of GSK-3 can increase glucose tolerance in diabetic mice. GSK-3 inhibitors may also have therapeutic effects on hemorrhagic transformation after acute ischemic stroke. GSK-3 can negatively regulate
2016-427: The adaptive immune response by inducing cytokine production and proliferation in naïve and memory CD4+ T cells. In cellular migration, an integral aspect of inflammatory responses, the inhibition of GSK-3 has been reported to play conflicting roles, as local inhibition at growth cones has been shown to promote motility while global inhibition of cellular GSK-3 has been shown to inhibit cell spreading and migration. GSK-3
2072-463: The anti-GSK-3β hypothesis of naproxen and cromolyn, docking of the two structures against GSK-3β binding pocket and comparing their fitting with known GSK-3β inhibitor ARA014418 was performed, in addition to measuring the serum glucose, serum insulin, serum C-peptide, weight variation and hepatic glycogen levels for normal and diabetic fasting animal's models to assess their in vitro hypoglycemic effects. Naproxen and cromolyn were successfully docked into
2128-440: The binding pocket of GSK-3β making significant interactions with key points within the GSK-3β binding pocket. Strong hydrogen bond interactions with the key amino acids PRO-136 and VAL -135 and potential hydrophobic interaction with LEU-188 were similar to those found in the ligand binding to the enzyme (AR-A014418). Furthermore, famotidine showed high GSK-3β binding affinity and inhibitory activity due to interactions that stabilize
2184-432: The binding site of GSK-3β (both were fitted into its binding pocket). They exhibited electrostatic, hydrophobic, and hydrogen-bonding interactions with key amino acids within the binding pocket with binding interaction profiles similar to AR-A014418 (the known inhibitor). The negative charges of the carboxylic acid groups in both drugs interact electrostatically with the positively charged guanidine group of Arg141. Moreover,
2240-611: The brain, and recently it shows anti-malarial activity. Curcumin also has chemo preventative and anti-cancer effects, and it has been shown to attenuate oxidative stress and renal dysfunction in diabetic animals with chronic use. Curcumin's mechanism of action is anti-inflammatory; it inhibits the nuclear transcriptional activator kappa B ( NF-KB ) that is activated whenever there is inflammatory response. NF-kB has two regulatory factors, IkB and GSK-3, which suggests curcumin directly binds and inhibits GSK-3B. An in vitro study confirmed GSK-3B inhibition by simulating molecular docking using
2296-466: The brain, soon after the discovery of D -aspartate . Had D amino acids been discovered in humans sooner, the glycine site on the NMDA receptor might instead be named the D -serine site. Apart from central nervous system, D -serine plays a signaling role in peripheral tissues and organs such as cartilage, kidney, and corpus cavernosum. Pure D -serine is an off-white crystalline powder with
GSK-3 - Misplaced Pages Continue
2352-683: The complex, namely hydrogen bonding of guanidine group in famotidine with the sulfahydryl moiety in CYS-199; and electrostatic interactions between the same guanidine group with the carboxyl group in ASP-200, the hydrogen bond between the terminal NH2 group, the OH of the TYR-143, and the hydrophobic interaction of the sulfur atom in the thioether with ILE-62. In vitro studies showed that famotidine inhibits GSK-3β activity and increases liver glycogen reserves in
2408-455: The dual-specificity tyrosine phosphorylation-regulated kinase, are also phosphorylated by GSK3, causing them to be degraded. GSK-3 also participates in a number of apoptotic signaling pathways by phosphorylating transcription factors that regulate apoptosis . GSK-3 can promote apoptosis by both activating pro-apoptotic factors such as p53 and inactivating survival-promoting factors through phosphorylation. The role of GSK-3 in regulating apoptosis
2464-402: The formation of protein complexes. The activity of GSK-3 is far greater in the nucleus and mitochondria than in the cytosol in cortical neurons, while the phosphorylation of Beta-catenin by GSK-3 is mediated by the binding of both proteins to Axin , a scaffold protein, allowing Beta-catenin to access the active site of GSK-3. Insulin indirectly inactivates GSK3 via downstream phosphorylation of
2520-502: The gluconeogenic enzymes phosphoenolpyruvate carboxykinase and glucose 6 phosphatase . However, these interactions have not been confirmed, as these pathways can be inhibited without the up-regulation of GSK-3. GSK-3 has also been shown to regulate immune and migratory processes. GSK-3 participates in a number of signaling pathways in the innate immune response, including pro-inflammatory cytokine and interleukin production. The inactivation of GSK3B by various protein kinases also affects
2576-407: The human body under normal physiological circumstances, making it a nonessential amino acid. It is encoded by the codons UCU, UCC, UCA, UCG, AGU and AGC. This compound is one of the proteinogenic amino acids . Only the L - stereoisomer appears naturally in proteins. It is not essential to the human diet, since it is synthesized in the body from other metabolites , including glycine . Serine
2632-525: The hydrogen bonding interactions between carboxylic acid moieties of cromolyn and the ammonium groups of Lys183 and Lys60, in addition to π-stacking of the naphthalene ring system of naproxen with the phenolic ring of Tyr134. Antidiabetic effects of naproxen and cromolyn: In normal animal models, both drugs have showed dose-dependent reduction in blood glucose levels and rise in glycogen levels. In chronic type II diabetic model, glucose levels were also reduced, and glycogen level and insulin levels were elevated in
2688-436: The insulin signaling pathway by inhibiting IRS1 via phosphorylation of serine-332, rendering the insulin receptor incapable of activating IRS1 and further initiating the canonical PI3K/Akt pathway. The role that inhibition of GSK-3 might play across its other signaling roles is not yet entirely understood. GSK-3 inhibition also mediates an increase in the transcription of the transcription factor Tbet (Tbx21) and an inhibition of
2744-583: The regulation of glucose metabolisms, such as myo-inositol-1-monophosphatase and 1,6 bisphosphatase. Also, it has shown therapeutic benefit in Alzheimer's and other neurodegenerative diseases such as epileptic neurodegeneration. Naproxen is a non-steroidal anti-inflammatory drug while cromolyn is an anti-allergic agent which acts as a mast cell stabilizer. Both drugs have demonstrated the anticancer effect in addition to hypoglycemic effect due to inhibition of glycogen synthase kinase-3β (GSK-3β). To validate
2800-472: The risk of extrapyramidal symptoms, such as tardive dyskinesia , and have better efficacy. Olanzapine and atypical antipsychotics induce weight gain through increasing body fat. It also affects glucose metabolism, and several studies shows that it may worsen diabetes. A recent study shows that olanzapine inhibits GSK3 activity, suggesting olanzapine permits glycogen synthesis. A study of the effect of olanzapine on mouse blood glucose and glycogen levels showed
2856-563: The specific serine residues Ser21 and Ser9 in GSK-3 isoforms α and β, respectively via the PI3K/Akt pathway . As of 2019, GSK-3 is the only type of glycogen synthase kinase named and recognized. The gene symbols for GSK1 and GSK2 have been withdrawn by the HUGO Gene Nomenclature Committee (HGNC), and no new names for these "genes" nor their locations have been specified. GSK-3 functions by phosphorylating
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#17327760920982912-502: The specific serine residues Ser21 and Ser9 in GSK-3 isoforms α and β, respectively, via the PI3K/Akt pathway (protein kinase B). Due to its involvement in a great number of signaling pathways, GSK-3 has been associated with a host of high-profile diseases. GSK-3 inhibitors are currently being tested for therapeutic effects in Alzheimer's disease , type 2 diabetes mellitus (T2DM), some forms of cancer , and bipolar disorder . There
2968-480: The subject of much research since it has been implicated in a number of diseases, including type 2 diabetes , Alzheimer's disease , inflammation , cancer , addiction and bipolar disorder . GSK-3 is a serine/threonine protein kinase that phosphorylate either threonine or serine , and this phosphorylation controls a variety of biological activities, such as glycogen metabolism, cell signaling , cellular transport , and others. GS inhibition by GSK-3β leads to
3024-543: The transcription of the inhibitory co-receptor programmed cell death-1 (PD-1) on T-cells. GSK-3 inhibitors increased in vivo CD8(+) OT-I CTL function and the clearance of viral infections by murine gamma-herpesvirus 68 and lymphocytic choriomeningitis clone 13 as well as anti-PD-1 in immunotherapy. Glycogen synthase kinase inhibitors are different chemotypes and have variable mechanisms of action; they may be cations , from natural sources, synthetic ATP and non-ATP competitive inhibitors and substrate-competitive inhibitors. GSK3
3080-618: Was first obtained from silk protein, a particularly rich source, in 1865 by Emil Cramer. Its name is derived from the Latin for silk, sericum . Serine's structure was established in 1902. The biosynthesis of serine starts with the oxidation of 3-phosphoglycerate (an intermediate from glycolysis ) to 3-phosphohydroxypyruvate and NADH by phosphoglycerate dehydrogenase ( EC 1.1.1.95 ). Reductive amination (transamination) of this ketone by phosphoserine transaminase ( EC 2.6.1.52 ) yields 3-phosphoserine ( O -phosphoserine) which
3136-440: Was originally discovered in the context of its involvement in regulating glycogen synthase . After being primed by casein kinase 2 (CK2), glycogen synthase gets phosphorylated at a cluster of three C-terminal serine residues, reducing its activity. In addition to its role in regulating glycogen synthase, GSK-3 has been implicated in other aspects of glucose homeostasis, including the phosphorylation of insulin receptor IRS1 and of
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