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The interaction of Hsp70s and lipids is conserved from bacteria to humans
Author(s) -
Siracusa Matthew Conrad,
Nikolaidis Nikolas
Publication year - 2013
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.27.1_supplement.1021.10
Subject(s) - biology , microbiology and biotechnology , chaperone (clinical) , cytosol , plasma protein binding , biochemistry , saccharomyces cerevisiae , protein targeting , membrane protein , yeast , membrane , medicine , pathology , enzyme
Hsp70s are molecular chaperones essential for protein homeostasis under both physiological and pathological conditions. Two mammalian Hsp70s, HSPA1A and HSPA8, have been found to associate with cellular membranes, where they bind to specific lipids. This binding localizes and anchors the chaperone to the plasma membrane, stabilizes the lysosomal membrane, regulates immune responses and cell signaling, and is required for microautophagy. Despite the essential role of membrane‐bound Hsp70s in immunogenic responses and cancer biology as well as cell signaling, the biological importance of Hsp70‐lipid interactions remains largely uncharacterized. Importantly, it remains unknown whether lipid‐binding is a function evolutionarily conserved in yeast and bacterial Hsp70s. In this study we examined the lipid‐binding properties of two yeast Hsp70s, the cytosolic SSA1 and the mitochondrial SSC1, and one bacterial Hsp70 and compared them to the mammalian Hsp70s. Our data demonstrate that although SSA1 and DnaK bind to several anionic lipids, SSC1 does not. Although further experimentation is required to determine the affinities and specificities of these interactions, our results suggest that lipid‐binding is an evolutionarily conserved property of Hsp70s and that they are functionally differentiated with respect to their lipid‐binding properties. This project was supported by funds from CSUPERB and CSUF to NN