The small heat shock proteins, HSPB1 and HSPB5, interact differently with lipid membranes.

摘要: Increasing evidence shows that heat shock proteins (hsp) escape the cytosol gaining access to extracellular environment, acting as signaling agents. Since majority of these lack information necessary for their export via classical secretory pathway, attention has been focused on alternative releasing mechanisms. Crossing plasma membrane is a major obstacle secretion cytosolic protein into milieu. Several mechanisms have proposed, including direct interaction with or release within vesicles (ECV). HSPB1 (Hsp27), which belongs small hsp family, was detected ECV released from stressed HepG2 cells. To further investigate this finding, we studied lipid membranes using liposomes. We found interacted liposomes made palmitoyl oleoyl phosphatidylserine (POPS), phosphatidylcholine (POPC), and phosphatidylglycerol (POPG), different characteristics. Another member HSPB5 (αB-crystallin), also HeLa cells transfected gene. This interact well, but differently than HSPB1. address regions interacting membrane, proteoliposomes were digested proteinase K protected domains identified by mass spectroscopy. observed large parts embedded liposomes, particularly alpha-crystallin domain. These observations suggest may be part proteins.