Component of the sarcoglycan complex, a subcomplex of the dystrophin-glycoprotein complex which forms a link between the F-actin cytoskeleton and the extracellular matrix. Interacts with the syntrophin SNTA1. Cross-link to form 2 major subcomplexes: one consisting of SGCB, SGCD and SGCG and the other consisting of SGCB and SGCD. The association between SGCB and SGCG is particularly strong while SGCA is loosely associated with the other sarcoglycans. Interacts with FLNC (By similarity). Disulfide bonds are present. Belongs to the sarcoglycan beta/delta/gamma/zeta family.