UNIPROT #

P07384

PROTEIN NAME

Calpain 1

SYNONYMS

Ca2 activated neutral protease antibody; Calcium activated neutral proteinase antibody; Calcium activated neutral proteinase small subunit antibody; Calcium dependent protease small subunit 1 antibody; Calcium dependent protease small subunit antibody; Calcium-activated neutral proteinase 1 antibody; Calpain 1 antibody; Calpain 1 large subunit antibody; Calpain 1, (mu/I) large subunit antibody; Calpain mu type antibody; Calpain mu-type antibody; Calpain regulatory subunit antibody; Calpain small subunit 1 antibody; Calpain, large polypeptide L1 antibody; Calpain-1 catalytic subunit antibody; Calpain-1 large subunit antibody; CAN1_HUMAN antibody; CANP 1 antibody; CANP antibody; CANP small subunit antibody; CANP1 antibody; CANPL 1 antibody; CANPL1 antibody; CAPN 1 antibody; CAPN1 antibody; Cell proliferation inducing protein 30 antibody; Cell proliferation-inducing gene 30 protein antibody; Micromolar Calpain antibody; Micromolar-calpain antibody; Mu Calpain antibody; muCANP antibody; muCL antibody

SEQUENCE SIMILARITIES

Belongs to the peptidase C2 family.

TISSUE SPECIFICITY

Ubiquitous.

POST-TRANSLATIONAL MODIFICATION

Undergoes calcium-induced successive autoproteolytic cleavages that generate a membrane-bound 78 kDa active form and an intracellular 75 kDa active form. Calpastatin reduces with high efficiency the transition from 78 kDa to 75 kDa calpain forms.

SUBCELLULAR LOCATION

Plama membrane.

FUNCTION

Calpain 1 (large subunit), also designated µ-calpain, is an intracellular calcium-dependent protease that cleaves cyto-skeletal and submembranous proteins. Calpains are nonlysosomal, calcium-activated intracellular cysteine proteases. Calpains mediate specific Ca2+-dependent processes including cell fusion, mitosis and meiosis. Calpains are heterodimers of a small regulatory subunit and one of three large catalytic subunits, designated Calpain 1 (large subunit), Calpain 2 and Calpain p94. Calpastatin regulates Calpain by inhibiting both the proteolytic activity of Calpain and its binding to membranes. Calpastatin exists in two types, tissue type and erythrocyte type, resulting from both alternative splicing and proteolytic processing. Calpain-1 co-localizes with human leukocyte antigen-DR (HLA-DR) on activated microglia in the aging brain. Calpain influences the process of spermatogenesis and the events preceding fertilization, such as the acrosome reaction.