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Activation of phospholipase C by heat shock requires GTP analogs and is resistant to pertussis toxin
Author(s) -
Calderwood Stuart K.,
Stevenson Mary Ann,
Price Brendan D.
Publication year - 1993
Publication title -
journal of cellular physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.529
H-Index - 174
eISSN - 1097-4652
pISSN - 0021-9541
DOI - 10.1002/jcp.1041560121
Subject(s) - pertussis toxin , phospholipase c , phospholipase , heat shock protein , g protein , microbiology and biotechnology , gtp' , heat shock , biology , phospholipase a2 , population , signal transduction , biochemistry , chemistry , enzyme , medicine , environmental health , gene
The heat shock response in mammals consists of a complex array of intracellular reactions initiated by stress, although its regulation is poorly understood. We have investigated the role of transmembrane signal transduction in the response, examining mechanisms involved in the activation of phospholipase C (PLC) by heat shock. In rodent fibroblasts permeabilized with digitonin, heat shock and receptor‐mediated PLC activity exhibited a strict GTP analog dependency. This indicates that heat shock‐mediated phopholipase activation, in common with receptor mediated stimulation, does not involve direct effects on the phospholipases and suggests the participation of GTP binding (G) proteins in the activation process. When cells were treated with the inhibitor pertussis toxin (PTX), the phospholipases retained their inducibility by heat shock, but became refractory to thrombin treatment, indicating that heat shock may influence PLC activity through a distinct population of G proteins compared to thrombin. The data seem to exclude a role for PTX sensitive G proteins in the production of IP 3 after heating and suggest a pathway involving the direct thermal activation of the G q class of G proteins, which are coupled to the PLC β1 isoform. © 1993 Wiley‐Liss, Inc.