Calpain small subunit 1 (CSS1)

Calpain small subunit 1 is the essential regulatory partner for calpain-1 and calpain-2, two calcium-dependent cysteine proteases. It is required for the stability and activity of these heterodimeric proteases, enabling controlled proteolysis of substrates involved in cytoskeletal remodeling and cell signaling. This subunit contains an N-terminal domain rich in glycine and a Ca-binding C-terminal domain, and its genetic variants have been implicated in myotonic dystrophy and cancer progression. CAPNS1 is crucial for embryonic development and is explored as a therapeutic target, though no approved drugs specifically modulate its function at present[1][2][3][6].

Other names

Calcium-activated neutral proteinase small subunitCalcium-dependent protease small subunitCalcium-dependent protease small subunit 1Calpain regulatory subunitCANP small subunitCAPNSCAPN4 (rat)CDPSCSS1

Allosteric inhibition of calpain heterodimerization (disrupting CAPNS1 interaction with large subunits); Competitive inhibition at the active site of calpain proteases (general calpain inhibitors)