Premium
Determination of the Intracellular, Surface, and Extracellular Localization of Hsp70s under Different Stress Conditions
Author(s) -
Medina Rebeca,
Rashedan Manely,
Nikolaidis Nikolas
Publication year - 2012
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.26.1_supplement.605.2
Subject(s) - extracellular , endoplasmic reticulum , intracellular , cytosol , secretion , microbiology and biotechnology , subcellular localization , mitochondrion , cell fractionation , chromosomal translocation , membrane , cell membrane , hsp70 , cellular compartment , biology , cytoplasm , biophysics , chemistry , cell , biochemistry , heat shock protein , enzyme , gene
Members of the Hsp70 family are primarily localized in different subcellular compartments, including the cytosol, endoplasmic reticulum, and mitochondria. Apart from their primary localization, different Hsp70s have also been found in other places within the cell, as well as the cellular membrane and the extracellular milieu. However, it is unknown which stresses are responsible for their re‐localization, membrane translocation, and secretion. To this end we studied the localization of four members of the Hsp70 family under different stresses using sub‐cellular fractionation and confocal microscopy. These experiments revealed that under normal growth conditions all four Hsp70s were present in multiple fractions, as well as in the extracellular medium. In stressed cells, Hsp70 amounts in each fraction were significantly different from the untreated cells. These results suggest that stress causes re‐localization and differential membrane‐anchorage and secretion of the four Hsp70s. Additional experiments using pharmacological manipulation of intracellular trafficking pathways are currently being performed to identify the molecular mechanism used by Hsp70s to achieve their translocation, membrane anchorage, and subsequent secretion. This study is the first step towards elucidating the biological importance of the re‐localization and membrane occurrence of these chaperones. This project was supported by funds from CSUPERB and CSUF to NN.