
Heterotrimeric Galphaq11 co-immunoprecipitates with surface-anchored GRP78 from plasma membranes of alpha2M*-stimulated macrophages.
We have previously shown that a fraction of newly expressed GRP78 is translocated to the cell surface in association with the co-chaperone MTJ-1. Proteinase and methylamine-activated alpha(2)M (alpha(2)M*) bind to cell surface-associated GRP78 activating phosphoinositide-specific phospholipase C coupled to a pertussis toxin-insensitive heterotrimeric G protein, generating IP(3)/calcium signaling. We have now studied the association of pertussis toxin-insensitive Galphaq11, with GRP78/MTJ-1 complexes in the plasma membranes of alpha(2)M*-stimulated macrophages. When GRP78 was immunoprecipitated from plasma membranes of macrophages stimulated with alpha(2)M*, Galphaq11, and MTJ-1 were co-precipitated. Likewise Galphaq11 and GRP78 co-immunoprecipitated with MTJ-1 while GRP78 and MTJ-1 co-immunoprecipitated with Galphaq11. Silencing GRP78 expression with GRP78 dsRNA or MTJ-1 with MTJ-1 dsRNA greatly reduced the levels of Galphaq11 co-precipitated with GRP78 or MTJ-1. In conclusion, we show here that plasma membrane-associated GRP78 is coupled to pertussis toxin-insensitive Galphaq11 and forms a ternary signaling complex with MTJ-1.
Duke Scholars
Altmetric Attention Stats
Dimensions Citation Stats
Published In
DOI
EISSN
Publication Date
Volume
Issue
Start / End Page
Location
Related Subject Headings
- Signal Transduction
- Molecular Chaperones
- Mice
- Membrane Proteins
- Macrophages
- Macrophage Activation
- Immunoprecipitation
- Heterotrimeric GTP-Binding Proteins
- Heat-Shock Proteins
- HSP40 Heat-Shock Proteins
Citation

Published In
DOI
EISSN
Publication Date
Volume
Issue
Start / End Page
Location
Related Subject Headings
- Signal Transduction
- Molecular Chaperones
- Mice
- Membrane Proteins
- Macrophages
- Macrophage Activation
- Immunoprecipitation
- Heterotrimeric GTP-Binding Proteins
- Heat-Shock Proteins
- HSP40 Heat-Shock Proteins