Interaction of human HSP22 (HSPB8) with other small heat shock proteins.
Mammalian small heat shock proteins (sHSP) are abundant in muscles and are implicated in both muscle function and myopathies. Recently a new sHSP, HSP22 (HSPB8, H11), was identified in the human heart by its interaction with HSP27 (HSPB1). Using phylogenetic analysis we show that HSP22 is a true member of the sHSP superfamily. sHSPs interact with each other and form homo- and hetero-oligomeric complexes. The function of these complexes is poorly understood. Using gel filtration HPLC, the yeast two-hybrid method, immunoprecipitation, cross-linking, and fluorescence resonance energy transfer microscopy, we report that (i). HSP22 forms high molecular mass complexes in the heart, (ii). HSP22 interacts with itself, cvHSP (HSPB7), MKBP (HSPB2) and HSP27, and (iii). HSP22 has two binding domains (N- and C-terminal) that are specific for different binding partners. HSP22 homo-dimers are formed through N-N and N-C interactions, and HSP22-cvHSP hetero-dimers through C-C interaction. HSP22-MKBP and HSP22-HSP27 hetero-dimers involve the N and C termini of HSP22 and HSP27, respectively, but appear to require full-length protein as a binding partner.
Departments of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, Michigan 48109, USA.
Xiankui
X
Sun
Jean-Marc
JM
Fontaine
Joshua S
JS
Rest
Eric A
EA
Shelden
Michael J
MJ
Welsh
Rainer
R
Benndorf
D003001:Cloning, Molecular; D019281:Dimerization; D006360:Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D018832:Molecular Chaperones; D010802:Phylogeny; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases; D017434:Protein Structure, Tertiary
C413214:HSPB8 protein, human; D006360:Heat-Shock Proteins; D018832:Molecular Chaperones; D017346:Protein Serine-Threonine Kinases