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Intracellular distribution of heat‐induced stress glycoproteins
Author(s) -
Jethmalani Sunita M.,
Henle Kurt J.,
Gazitt Yair,
Walker Patrick D.,
Wang ShoYa
Publication year - 1997
Publication title -
journal of cellular biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.028
H-Index - 165
eISSN - 1097-4644
pISSN - 0730-2312
DOI - 10.1002/(sici)1097-4644(19970701)66:1<98::aid-jcb11>3.0.co;2-9
Subject(s) - cytosol , glycoprotein , differential centrifugation , cell fractionation , heat shock protein , hsp70 , mitochondrion , microsome , intracellular , subcellular localization , biochemistry , biology , microbiology and biotechnology , stress granule , cellular compartment , heat shock , cytoplasm , cell , enzyme , translation (biology) , messenger rna , gene
Cellular heat stress results in elevated heat‐shock protein (HSP) synthesis and in thermotolerance development. Recently, we demonstrated that protein glycosylation is also an integral part of the stress response with the identification of two major stress glycoproteins, GP50, associated with thermotolerance, and P‐SG67, the “prompt” stress glycoprotein induced immediately during acute heat stress. In the present study, we characterized the subcellular location and redistribution of these proteins during the cellular injury and recovery phase. In unheated and heated CHO cells, both stress glycoproteins were present in each subcellular fraction isolated by differential centrifugation. However, the subcellular redistribution in the course of cellular recovery after heat stress was specific for each stress glycoprotein. GP50 was present in all subcellular fractions before heat stress, but showed relatively little redistribution after heat stress. By 24 h of recovery following stress, GP50 showed partial depletion from lysosomes and microsomes, and was mainly present in the mitochondria. Glycosylated P‐SG67 was redistributed in a more complex fashion. It was seen predominantly in the lysosomes and microsomes immediately following heat‐stress, but after 6 h of recovery following heat stress, it largely disappeared from the microsomes and was present mainly in the cytosol. By 24 h of recovery following heat stress, it was found predominantly in the nucleus‐rich fraction and mitochondria. The localization of GP50 and P‐SG67 by subcellular fractionation is consistent with immunolocalization studies and contrasts with the translocation of HSP70 after heat stress from cytosol to nuclei and nucleoli. These results reflect a characteristic distribution for each stress glycoprotein; their presence in virtually all subcellular fractions suggests multifunctional roles for the various stress glycoproteins in the cellular heat stress response. J. Cell. Biochem. 66:98–111, 1997. © 1997 Wiley‐Liss, Inc.