protein kinase C conserved region 1 (C1 domain) found in SH3 and cysteine-rich domain-containing protein 3 (Stac3) and similar proteins
Stac3 is an essential component of the skeletal muscle excitation-contraction coupling (ECC) machinery. It is required for normal excitation-contraction coupling in skeletal muscle and for normal muscle contraction in response to membrane depolarization. It plays an essential role for normal Ca2+ release from the sarcplasmic reticulum, which ultimately leads to muscle contraction. Stac3 contains a cysteine-rich C1 domain and two SH3 domains at the C-terminus. This model corresponds to the C1 domain. The C1 domain is a cysteine-rich zinc binding domain that does not bind DNA nor possess structural similarity to conventional zinc finger domains; it contains two separate Zn(2+)-binding sites.