Structure, function, property, and role in neurologic diseases and other diseases of the sHsp22

Small heat shock proteins are members of the heat shock proteins family. They share important identical features: 1) they form the conserved structure ‘α‐crystallin domain’ with about 80–100 residues in the C‐terminal part of the proteins; 2) they have monomeric molecular masses ranging in 12–43 kDa; 3) they associate into large oligomers consisting in many cases of subunits; 4) they increase expression under stress conditions; 5) they exhibit a highly dynamic structure; and 6) they play a chaperone‐like role. Hsp22 (also known as HspB8, H11, and E2IG1) retains the structural motif of the ‘α‐crystallin’ family of Hsps and is a member of the superfamily of sHsps. Hsp22 displays chaperone activity, autokinase activity, and trigger or block apoptosis activity. It differs from canonical family members existing as a monomer. A decrease in the HspB8 activity may contribute to the development of some neurologic diseases and others. © 2007 Wiley‐Liss, Inc.