calponin homology (CH) domain found in the smoothelin family
The smoothelin family includes smoothelin and smoothelin-like proteins. Smoothelins are actin-binding cytoskeletal proteins that are abundantly expressed in healthy visceral (smoothelin-A) and vascular (smoothelin-B) smooth muscle. SMTNL1, also called calponin homology-associated smooth muscle protein (CHASM), plays a role in the regulation of contractile properties of both striated and smooth muscles. It can bind to calmodulin and tropomyosin. When it is unphosphorylated, SMTNL1 may inhibit myosin dephosphorylation. SMTNL2 is highly expressed in skeletal muscle and could be associated with differentiating myocytes. Members of this family contain a single copy of the CH domain. CH domains are actin filament (F-actin) binding motifs.
Jiyao W et al.(2023). "The conserved domain database in 2023.",