CNN1

Cnn1, also known as calponin-1, is a cytoskeletal protein encoded by the CNN1 gene in humans. It is a member of the calponin family of actin-binding proteins and is primarily expressed in smooth muscle cells, where it associates with actin filaments in the contractile apparatus.

Functionally, calponin-1 modulates smooth muscle contraction by inhibiting actin-activated myosin ATPase activity. Its regulatory effect is influenced by intracellular calcium through calmodulin and by phosphorylation via various kinases, which can alter its affinity for actin and the actomyosin complex.

In terms of structure and interactions, calponin-1 contains regions that bind F-actin and interact with other cytoskeletal components such as tropomyosin. It participates in the regulation of the thin filament apparatus and may play a role in cytoskeletal remodeling during muscle contraction, development, and tissue repair.

Expression and localization of CNN1 are enriched in vascular and visceral smooth muscle, with detectable levels in other tissues under certain conditions. Expression patterns can change during development and in disease states, reflecting modulations in smooth muscle function.

Clinical significance of calponin-1 includes associations with cardiovascular diseases involving smooth muscle remodeling, such as atherosclerosis and hypertension. Calponin-1 is also used as a marker of smooth muscle differentiation in research and pathology, helping to identify smooth muscle cells in tissue samples.

Family and evolution: Calponin-1 is one member of the calponin family, with related proteins that share actin-binding properties. These proteins are conserved across vertebrates and contribute to the regulation of cytoskeletal dynamics in muscle and non-muscle cells.

See also: Calponin; CNN2; CNN3; Smooth muscle.