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Functional Characterization of the Interactions of the 70‐kD Heat Shock Proteins (Hsp70s) with Lipids
Author(s) -
Nikolaidis Nikolas,
McCallister Chelsea Marie,
Donnelly Gabrielle,
Chaudhari Sunil
Publication year - 2011
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.25.1_supplement.907.3
Subject(s) - hsp70 , heat shock protein , biochemistry , plasma protein binding , biology , microbiology and biotechnology , membrane protein , chemistry , biophysics , membrane , gene
Hsp70s are essential for cellular homeostasis and survival. Apart from their functions as molecular chaperones, specific Hsp70s interact with lipids. It has been proposed that this interaction allows Hsp70s to stabilize biological membranes and be integral parts of signaling and trafficking pathways. Despite their importance, the Hsp70‐lipid interactions remain largely undefined, since it is unknown which Hsp70s bind to lipids and what types of lipids they bind. To this end, we generated recombinant proteins of three mouse Hsp70s, and by using protein lipid overlay and vesicle sedimentation assays we determined that these proteins bind to phospholipids with significantly different affinities and specificities. To further characterize the Hsp70‐lipid interactions and facilitate future mutagenesis analysis, we determined the precise location of the Hsp70‐lipid binding by generating overlapping fragments of the Hsp70 protein. Lipid‐binding assays revealed the presence of at least two regions on the Hsp70 molecule responsible for binding to lipids. Our data strongly suggest that Hsp70s are functionally differentiated with respect to their lipid‐binding properties. Moreover, the high specificity of the interaction of specific Hsp70s to particular lipids suggests that these interactions could facilitate their translocation, anchorage, and function at cellular membranes. This project was supported by funds from CSUPERB and CSUF to NN