Glycogen Synthase Kinase 3 B (GSK3B) (Ser9) (GSK3B) Antibody – Rabbit Polyclonal

Function: Constitutively active protein kinase that acts as a negative regulator in the hormonal control of glucose homeostasis, Wnt signaling and regulation of transcription factors and microtubules, by phosphorylating and inactivating glycogen synthase (GYS1 or GYS2), EIF2B, CTNNB1/beta-catenin, APC, AXIN1, DPYSL2/CRMP2, JUN, NFATC1/NFATC, MAPT/TAU and MACF1. Requires primed phosphorylation of the majority of its substrates. In skeletal muscle, contributes to insulin regulation of glycogen synthesis by phosphorylating and inhibiting GYS1 activity and hence glycogen synthesis. May also mediate the development of insulin resistance by regulating activation of transcription factors. Regulates protein synthesis by controlling the activity of initiation factor 2B (EIF2BE/EIF2B5) in the same manner as glycogen synthase. In Wnt signaling, GSK3B forms a multimeric complex with APC, AXIN1 and CTNNB1/beta-catenin and phosphorylates the N-terminus of CTNNB1 leading to its degradation mediated by ubiquitin/proteasomes. Phosphorylates JUN at sites proximal to its DNA-binding domain, thereby reducing its affinity for DNA. Phosphorylates NFATC1/NFATC on conserved serine residues promoting NFATC1/NFATC nuclear export, shutting off NFATC1/NFATC gene regulation, and thereby opposing the action of calcineurin. Phosphorylates MAPT/TAU on 'Thr-548', decreasing significantly MAPT/TAU ability to bind and stabilize microtubules. Plays an important role in ERBB2-dependent stabilization of microtubules at the cell cortex. Phosphorylates MACF1, inhibiting its binding to microtubules which is critical for its role in bulge stem cell migration and skin wound repair. Probably regulates NF-kappa-B (NFKB1) at the transcriptional level and is required for the NF-kappa-B-mediated anti-apoptotic response to TNF-alpha (TNF/TNFA). Negatively regulates replication in pancreatic beta-cells, resulting in apoptosis, loss of beta-cells. Through phosphorylation of the anti-apoptotic protein MCL1, may control cell apoptosis in response to growth factors deprivation. Phosphorylates MUC1 in breast cancer cells, decreasing the interaction of MUC1 with CTNNB1/beta-catenin. Is necessary for the establishment of neuronal polarity and axon outgrowth. Phosphorylates MARK2, leading to inhibit its activity. Phosphorylates SIK1 at 'Thr-182', leading to sustain its activity. Phosphorylates ZC3HAV1 which enhances its antiviral activity. Phosphorylates SFPQ upon T-cell activation. Phosphorylates SNAI1, leading to its BTRC-triggered ubiquitination and proteasomal degradation. Phosphorylates NR1D1 st 'Ser-55' and 'Ser-59' and stabilizes it by protecting it from proteasomal degradation. Ref.4 Ref.6 Ref.7

Catalytic activity: ATP + [tau protein] = ADP + [tau protein] phosphate.ATP + a protein = ADP + a phosphoprotein.

Enzyme regulation: Activated by phosphorylation at Tyr-216. In response to insulin, inhibited by phosphorylation at Ser-9 by PKB/AKT1; phosphorylation at this site causes a conformational change, preventing access of substrates to the active site. Inhibited by lithium.

Subunit structure: Monomer. Interacts with DAB2IP (via C2 domain); the interaction stimulates GSK3B kinase activation. Interacts (via C2 domain) with PPP2CA

By similarity. Interacts with ARRB2, AXIN1, CABYR, DISC1, MMP2, MUC1, NIN, PRUNE and ZBED3

By similarity. Interacts with AXIN1; the interaction mediates hyperphosphorylation of CTNNB1 leading to its ubiquitination and destruction. Interacts with and phosphorylates SNAI1. Interacts with DNM1L (via a C-terminal domain)

By similarity. Found in a complex composed of MACF1, APC, AXIN1, CTNNB1 and GSK3B. Interacts with SGK3

By similarity. Ref.4 Ref.5

Subcellular location: Cytoplasm

By similarity. Nucleus

By similarity. Membrane. Cell membrane

By similarity. Note: The phosphorylated form shows localization to cytoplasm and cell membrane. The MEMO1-RHOA-DIAPH1 signaling pathway controls localization of the phosphorylated form to the cell membrane

By similarity. Ref.5

Post-translational modification: Phosphorylated by AKT1 and ILK1. Upon insulin-mediated signaling, the activated PKB/AKT1 and RPS6KA3 protein kinases phosphorylate and desactivate GSK3B, resulting in the dephosphorylation and activation of GYS1. Activated by phosphorylation at Tyr-216

By similarity. Ref.3Mono-ADP-ribosylation by PARP10 negatively regulates kinase activity

By similarity.

Miscellaneous: Simultaneous silencing of GSK3A and GSK3B by RNAi stimulates replication and promotes survival of INS-1E pancreatic beta cells (Ref.6).

Sequence similarities: Belongs to the protein kinase superfamily. CMGC Ser/Thr protein kinase family. GSK-3 subfamily.Contains 1 protein kinase domain.