Calponin-1

Calponin-1 (CNN1) is a thin filament-associated protein that regulates smooth muscle contraction through its interactions with actin, calmodulin, and tropomyosin. By inhibiting actomyosin Mg-ATPase activity, it modulates contractile force generation (UniProt: P51911). The protein is expressed primarily in smooth muscle tissues where it functions as a key regulatory component of the contractile apparatus.

Calponin-1 has not been explicitly annotated with disease associations in UniProt, though its role in cytoskeletal dynamics may have broader cellular implications. In Alzheimer's Disease, calponin-1 shows consistent upregulation in post-mortem brain tissue from AD patients compared to age-matched controls, with a mean log2 fold-change of +1.86 (Chaparral AD proteomics). This elevation was detected across a single subcellular fraction in a TMT-labeled quantitative proteomics study examining four subcellular compartments (P2, P3, S2, S3). The functional significance of increased calponin-1 in AD brain remains to be clarified, though altered cytoskeletal organization is a recognized feature of AD neuropathology.