HSPB1
This gene encodes a member of the small heat shock protein (HSP20) family of proteins. In response to environmental stress, the encoded protein translocates from the cytoplasm to the nucleus and functions as a molecular chaperone that promotes the correct folding of other proteins. This protein plays an important role in the differentiation of a wide variety of cell types. Expression of this gene is correlated with poor clinical outcome in multiple human cancers, and the encoded protein may promote cancer cell proliferation and metastasis, while protecting cancer cells from apoptosis. Mutations in this gene have been identified in human patients with Charcot-Marie-Tooth disease and distal hereditary motor neuropathy.
Full Name
heat shock protein family B (small) member 1
Alternative Names
CMT2F; HMN2B; HSP27; HSP28; Hsp25; SRP27; HS.76067; HEL-S-102
Function
Small heat shock protein which functions as a molecular chaperone probably maintaining denatured proteins in a folding-competent state (PubMed:10383393, PubMed:20178975).
Plays a role in stress resistance and actin organization (PubMed:19166925).
Through its molecular chaperone activity may regulate numerous biological processes including the phosphorylation and the axonal transport of neurofilament proteins (PubMed:23728742).
Biological Process
Anterograde axonal protein transport Source: UniProtKB
Cellular response to vascular endothelial growth factor stimulus Source: BHF-UCL
Chaperone-mediated protein folding Source: UniProtKB
Intracellular signal transduction Source: BHF-UCL
Negative regulation of apoptotic process Source: UniProtKB
Negative regulation of oxidative stress-induced intrinsic apoptotic signaling pathway Source: BHF-UCL
Negative regulation of protein kinase activity Source: BHF-UCL
Platelet aggregation Source: UniProtKB
Positive regulation of angiogenesis Source: BHF-UCL
Positive regulation of blood vessel endothelial cell migration Source: BHF-UCL
Positive regulation of endothelial cell chemotaxis Source: BHF-UCL
Positive regulation of endothelial cell chemotaxis by VEGF-activated vascular endothelial growth factor receptor signaling pathway Source: BHF-UCL
Positive regulation of interleukin-1 beta production Source: BHF-UCL
Positive regulation of tumor necrosis factor production Source: BHF-UCL
Regulation of autophagy Source: ParkinsonsUK-UCL
Regulation of I-kappaB kinase/NF-kappaB signaling Source: BHF-UCL
Regulation of protein phosphorylation Source: UniProtKB
Regulation of translational initiation Source: ProtInc
Response to unfolded protein Source: ProtInc
Response to virus Source: UniProtKB
Retina homeostasis Source: UniProtKB
Cellular Location
Cytoplasm; Spindle; Nucleus. Cytoplasmic in interphase cells. Colocalizes with mitotic spindles in mitotic cells. Translocates to the nucleus during heat shock and resides in sub-nuclear structures known as SC35 speckles or nuclear splicing speckles.
Involvement in disease
Charcot-Marie-Tooth disease 2F (CMT2F):
A dominant axonal form of Charcot-Marie-Tooth disease, a disorder of the peripheral nervous system, characterized by progressive weakness and atrophy, initially of the peroneal muscles and later of the distal muscles of the arms. Charcot-Marie-Tooth disease is classified in two main groups on the basis of electrophysiologic properties and histopathology: primary peripheral demyelinating neuropathies (designated CMT1 when they are dominantly inherited) and primary peripheral axonal neuropathies (CMT2). Neuropathies of the CMT2 group are characterized by signs of axonal degeneration in the absence of obvious myelin alterations, normal or slightly reduced nerve conduction velocities, and progressive distal muscle weakness and atrophy. Onset of Charcot-Marie-Tooth disease type 2F is between 15 and 25 years with muscle weakness and atrophy usually beginning in feet and legs (peroneal distribution). Upper limb involvement occurs later.
Neuronopathy, distal hereditary motor, 2B (HMN2B):
A neuromuscular disorder. Distal hereditary motor neuronopathies constitute a heterogeneous group of neuromuscular disorders caused by selective degeneration of motor neurons in the anterior horn of the spinal cord, without sensory deficit in the posterior horn. The overall clinical picture consists of a classical distal muscular atrophy syndrome in the legs without clinical sensory loss. The disease starts with weakness and wasting of distal muscles of the anterior tibial and peroneal compartments of the legs. Later on, weakness and atrophy may expand to the proximal muscles of the lower limbs and/or to the distal upper limbs.
PTM
Phosphorylated upon exposure to protein kinase C activators and heat shock (PubMed:8325890). Phosphorylation by MAPKAPK2 and MAPKAPK3 in response to stress dissociates HSPB1 from large small heat-shock protein (sHsps) oligomers and impairs its chaperone activity and ability to protect against oxidative stress effectively. Phosphorylation by MAPKAPK5 in response to PKA stimulation induces F-actin rearrangement (PubMed:1332886, PubMed:8093612, PubMed:19166925).
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