UNIPROT #

P04792

PROTEIN NAME

Heat shock protein beta-1

GENE NAME

HSPB1

SYNONYMS

HspB1, HSP 27, SRP27, HSPB1

SEQUENCE SIMILARITIES

Belongs to the small heat shock protein (HSP20) family.

TISSUE SPECIFICITY

Detected in all tissues tested: skeletal muscle, heart, aorta, large intestine, small intestine, stomach, esophagus, bladder, adrenal gland, thyroid, pancreas, testis, adipose tissue, kidney, liver, spleen, cerebral cortex, blood serum and cerebrospinal fluid. Highest levels are found in the heart and in tissues composed of striated and smooth muscle.

POST-TRANSLATIONAL MODIFICATION

Phosphorylated upon exposure to protein kinase C activators and heat shock. 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.

SUBCELLULAR LOCATION

Cytoplasm. Nucleus. Cytoplasm, cytoskeleton, spindle. Note=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.

FUNCTION

Small heat shock protein which functions as a molecular chaperone probably maintaining denatured proteins in a folding-competent state. Plays a role in stress resistance and actin organization. Through its molecular chaperone activity may regulate numerous biological processes including the phosphorylation and the axonal transport of neurofilament proteins.