A family of α-actinin type actin-binding proteins (nuclear envelope spectrin repeat proteins), distantly related to spectrin, that are transmembrane scaffolding proteins of the nuclear envelope. Nesprin-1 (synaptic nuclear envelope protein-1, syne-1, enaptin, myne, MSP-300, Ank-1, 8797 aa) and nesprin-2 (6885 aa) connect to the actin cytoskeleton through an N-terminal actin-binding domain and a C-terminal region that binds Sun1 of the inner membrane. Nesprin-3 (975 aa), an outer nuclear envelope membrane protein, lacks an actin-binding domain but associates with the linker protein plectin. A large isoform of nesprin-2 (Nesprin-2 Giant; 800- kDa) is also found on the cytoplasmic membrane of the nuclear envelope. Mutations in nesprin-1 cause spinocerebellar ataxia type 8.
Subjects: Medicine and Health.