Publication Date:
1991-12-20
Description:
Rap1A is a low molecular weight guanosine triphosphate (GTP)-binding protein in human neutrophil membranes whose cellular function is unknown. Rap1A was found to form stoichiometric complexes with the cytochrome b558 component of the phagocyte nicotinamide adenine dinucleotide phosphate (NADPH) oxidase system. The (guanosine-5'-O-(3-thiotriphosphate) (GTP-gamma-S)-bound form of Rap1A bound more tightly to cytochrome b558 than did the guanosine diphosphate-bound form. No complex formation was observed between cytochrome b558 and H-Ras-GTP-gamma-S or Rap1A-GTP-gamma-S that had been heat-inactivated, nor between Rap1A-GTP-gamma-S and hydrophobic proteins serving as controls. Complex formation between Rap1A-GTP-gamma-S and cytochrome b558 was inhibited by phosphorylation of Rap1A with cyclic adenosine monophosphate (cAMP)-dependent protein kinase. These observations suggest that Rap1A may participate in the structure or regulation of the NADPH oxidase system and that this function of the Rap1A protein may be altered by phosphorylation.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Bokoch, G M -- Quilliam, L A -- Bohl, B P -- Jesaitis, A J -- Quinn, M T -- 5RO126711/PHS HHS/ -- GM39434/GM/NIGMS NIH HHS/ -- GM44428/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1991 Dec 20;254(5039):1794-6.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Immunology, Scripps Research Institute, La Jolla, CA 92037.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/1763330" target="_blank"〉PubMed〈/a〉
Keywords:
Binding Sites
;
Chromatography, Gel
;
Cytochrome b Group/isolation & purification/*metabolism
;
GTP-Binding Proteins/antagonists & inhibitors/isolation &
;
purification/*metabolism
;
Guanosine 5'-O-(3-Thiotriphosphate)/metabolism
;
Humans
;
Kinetics
;
Macromolecular Substances
;
NADH, NADPH Oxidoreductases/*metabolism
;
NADPH Oxidase
;
Neutrophils/enzymology
;
Phosphorylation
;
Protein Binding
;
Protein Kinase C/metabolism
;
Proto-Oncogene Proteins/metabolism
;
Recombinant Proteins/antagonists & inhibitors/isolation & purification/metabolism
;
rap GTP-Binding Proteins
Print ISSN:
0036-8075
Electronic ISSN:
1095-9203
Topics:
Biology
,
Chemistry and Pharmacology
,
Computer Science
,
Medicine
,
Natural Sciences in General
,
Physics
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