S100 ? (A18) polyclonal antibody detects endogenous levels of S100 A1 protein.

The family of EF-hand type Ca2+-binding proteins includes calbindin (previously designated vitamin D-dependent Ca 2+-binding protein), S-100 ? and ?, calgranulins A (also designated MRP8), B (also designated MRP14) and C (S-100 like proteins), and the parvalbumin family members, including parvalbumin ? and parvalbumin ? (also designated oncomodulin). The S-100 protein is involved in the regulation of cellular processes such as cell cycle progression and differentiation. Research also indicates that the S-100 protein may function in the activation of Ca2+ induced Ca2+ release, inhibition of microtubule assembly and inhibition of protein kinase C mediated phosphorylation. Two S-100 subunits, sharing 60% sequence identity, have been described as S-100? chain and S-100? chain. Three S-100 dimeric forms have been characterized, differing in their subunit composition of either two ? chains, two ? chains or one ? and one ? chain.