Heat Shock Protein beta-8, HspB8, Alpha-crystallin C Chain, H11, CRYAC, HSP22, DHMN2, CMT2L, Heat Shock 22kD Protein 8

Hsp22 (HSPB8) is a 196aa protein that is a member of the small heat shock protein super-family and the human protein is most closely related to Hsp27. Similar to most other sHSPs, Hsp22 is predominately transcribed in skeletal muscle and heart, as well as the placenta (1). Hsp22 is a monomeric protein which interacts with HSPB1. It displays temperature-dependent chaperone activity. In a two hybrid screen, HspB8 interacted preferentially with a triple aspartate form of Hsp27 which mimics Hsp27 phosphorylated at Ser15, Ser78, and Ser82, as compared to wild-type Hsp27 (2). HSPB8 has two binding domains (N and C Terminal) that are specific for different binding partners, and has the ability to bind itself and other sHSPs (3). The chaperone-like activity is of great importance to the function of Hsp22 in various processes including proliferation, apoptosis and macroautophagy (4). Mutations in the HSPB8 gene are associated with the inherited peripheral neurpathies, autosomal dominant distal hereditary motor neuropathy type IIA (dSMA) and axonal Charcot-Marie-Tooth disease type 2L (CMT2L) (5).