HSPB2/MKBP, a novel and unique member of the small heat-shock protein family

Although proteins belonging to the sHSP superfamily are diverse in sequence and size, most share characteristic features, including 1) a small molecular mass of 12-43 kDa, 2) a conserved a-crystallin domain of 80-100 residues, 3) formation of large oligomers, 4) a dynamic quaternary structure, and 5) induction by stress conditions and chaperone activity in suppressing protein aggregation. HSPB2/MKBP (myotonic dystrophy kinase-bind-protein) retains the structural motif of the a-crystallin family of HSPs but shows a unique nature compared with canonical family members, characterized by gene allocation, specific binding partners in skeletal muscle, and unique stress responsiveness. MKBP may be involved in the pathogenesis of myotonic dystrophy and contribute to the neuropathology in both Alzheimer's disease and hereditary cerebral hemorrhage with amyloidosis, Dutch type. (c) 2008 Wiley-Liss, Inc.