Heat Shock Protein Beta 6 (HSPb6)

HSPB6 is associated with actin and modulates smooth muscle relaxation.Hsp20 coprecipitated with alpha-B crystallin (CRYAB) in a 200-kD protein aggregate. Immunofluorescence microscopy showed that the pattern of Hsp20, alpha-B crystallin, and actin staining was predominantly in transverse bands. Treatment of rat cardiac myocytes with sodium nitroprusside, an activator of cyclic nucleotide signaling, led to increased phosphorylation of Hsp20. Incubation of transiently permeabilized myocytes with phosphopeptide analogs of Hsp20 resulted in an increased rate of shortening, which was associated with an increased rate of lengthening and more rapid decay of calcium transients.Chemical crosslinking of wildtype HSP20 resulted in dimers of about 40 kD, and HSP20 formed heterooligomeric complexes with HSP27 (HSPB1).