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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
23
pubmed:dateCreated
1997-7-14
pubmed:abstractText
Palmitoylation is the dynamic modification of proteins by the addition of palmitate to cysteine residues. The alpha subunits of heterotrimeric G proteins undergo palmitoylation on their amino terminus, and activation of alpha(s) accelerates its palmitate turnover. In previous studies, palmitoylation was assessed by incorporation or turnover of [3H]palmitate. These studies did not determine the fraction of alpha(s) that is palmitoylated because the specific activity of [3H]palmitoyl-CoA within cells is indeterminate. We developed an HPLC method to determine the fraction of alpha(s) that was palmitoylated in the basal and activated states. COS and S49 cells were radiolabeled with [35S]methionine, and alpha(s) was immunoprecipitated from the particulate fraction. The immunoprecipitated proteins were separated by reverse phase HPLC into two peaks that were determined to contain the modified and unmodified forms of alpha(s). Approximately 77% of the endogenous alpha(s) in COS cells and 70% in S49 lymphoma cells were palmitoylated. The fraction of alpha(s) that was modified did not change after treatment with isoproterenol, a beta-adrenergic receptor agonist that causes turnover of palmitate on alpha(s). These results suggest that receptor activation of alpha(s) caused a rapid turnover of palmitate to maintain most of alpha(s) in its palmitoylated form.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
10
pubmed:volume
36
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
7185-91
pubmed:dateRevised
2009-11-19
pubmed:meshHeading
pubmed:year
1997
pubmed:articleTitle
The stoichiometry of G alpha(s) palmitoylation in its basal and activated states.
pubmed:affiliation
Metabolic Diseases Branch/National Institute of Diabetes, Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA. tlzj@helix.nih.gov
pubmed:publicationType
Journal Article