CAMK2B: a widely expressed protein kinase of the calcium/calmodulin-dependent protein kinase (CAMK) group. Functions autonomously after Ca2+/calmodulin-binding and autophosphorylation. Involved in dendritic spine and synapse formation, neuronal plasticity and regulation of sarcoplasmic reticulum Ca2+ transport in skeletal muscle. In neurons, plays an essential structural role in the reorganization of the actin cytoskeleton during plasticity by binding and bundling actin filaments in a kinase-independent manner. This structural function is required for correct targeting of CaMK2A, which acts downstream of NMDAR to promote dendritic spine and synapse formation and maintain synaptic plasticity which enables long-term potentiation (LTP) and hippocampus-dependent learning. In developing hippocampal neurons, promotes arborization of the dendritic tree and in mature neurons, promotes dendritic remodeling. Participates in the modulation of skeletal muscle function in response to exercise. In slow-twitch muscles, is involved in regulation of sarcoplasmic reticulum (SR) Ca2+ transport and in fast-twitch muscle participates in the control of Ca2+ release from the SR through phosphorylation of triadin, a ryanodine receptor-coupling factor, and phospholamban, an endogenous inhibitor of SERCA2. The holoenzyme is composed of 4 different chains: alpha (CAMK2A), beta (CAMK2B), gamma (CAMK2G), and delta (CAMK2D). The different isoforms assemble into homo- or heteromultimeric holoenzymes composed of 12 subunits with two hexameric rings stacked one on top of the other. Interacts with SYNGAP1 and CAMK2N2. Interacts with MPDZ. Expressed in adult and fetal brain. Expression is slightly lower in fetal brain. Expressed in skeletal muscle and induced during exercise. Eight isoforms of the human protein are produced by alternative splicing
Protein type: EC 2.7.11.17; Kinase, protein; Protein kinase, CAMK; Protein kinase, Ser/Thr (non-receptor); CAMK group; CAMK2 family
Chromosomal Location of Human Ortholog: 7p14.3-p14.1
Cellular Component: nucleoplasm; sarcoplasmic reticulum membrane; plasma membrane; microtubule organizing center; spindle midzone; cytosol
Molecular Function: calmodulin binding; protein homodimerization activity; calmodulin-dependent protein kinase activity; actin binding; ATP binding
Biological Process: regulation of long-term neuronal synaptic plasticity; regulation of skeletal muscle adaptation; protein amino acid autophosphorylation; cytokine and chemokine mediated signaling pathway; regulation of calcium ion transport; signal transduction; protein amino acid phosphorylation; regulation of synaptic transmission, cholinergic; inhibitory G-protein coupled receptor phosphorylation; synaptic transmission; peptidyl-serine phosphorylation; response to cadmium ion; calcium ion transport; regulation of synapse structural plasticity; neuromuscular process controlling balance; G1/S transition of mitotic cell cycle
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