Open AccessPersistent membrane association of activated and depalmitoylated G protein α subunits
Author(s) -
Changcheng Huang,
Joseph A. Duncan,
Alfred G. Gilman,
Susanne M. Mumby
Publication year - 1999
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.96.2.412
Subject(s) - heterotrimeric g protein , g beta gamma complex , g alpha subunit , g protein , microbiology and biotechnology , guanosine , membrane protein , gtp binding protein regulators , biology , vesicle associated membrane protein 8 , transport protein , biochemistry , signal transduction , protein subunit , membrane , gene
Heterotrimeric signal-transducing G proteins are organized at the inner surface of the plasma membrane, where they are positioned to interact with membrane-spanning receptors and appropriate effectors. G proteins are activated when they bind GTP and inactivated when they hydrolyze the nucleotide to GDP. However, the topological fate of activated G protein α subunits is disputed. One model declares that depalmitoylation of α, which accompanies activation by a receptor, promotes release of the protein into the cytoplasm. Our data suggest that activation of G protein α subunits causes them to concentrate in subdomains of the plasma membrane but not to be released from the membrane. Furthermore, α subunits remained bound to the membrane when they were activated with guanosine 5′-(3-O -thio)triphosphate and depalmitoylated with an acyl protein thioesterase. Limitation of α subunits to the plasma membrane obviously restricts their mobility and may contribute to the efficiency and specificity of signaling.