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Stimulus-induced dissociation of alpha subunits of heterotrimeric GTP-binding proteins from the cytoskeleton of human neutrophils.
| Content Provider | Semantic Scholar |
|---|---|
| Author | Särndahl, Eva Stendahl, Olle Andersson, Tommy |
| Copyright Year | 1993 |
| Abstract | Previous studies on the mechanism responsible for terminating the generation of second messengers induced by chemotactic factor-receptor complexes have, on one hand, suggested a direct role of a GTP-binding protein(s) (G protein), and, on the other hand, proposed that there is a lateral segregation of the ligand-receptor complexes into G protein-depleted domains of the plasma membrane. In the present investigation, which addresses these apparently contradictory findings, we found that a substantial part of the alpha subunits of the Gn protein (Gn alpha) in unstimulated neutrophils were associated with a cytoskeletal fraction and that release of these subunits occurred upon stimulation with the chemotactic factor fMet-Leu-Phe. An identical Gn alpha release could also be induced by direct activation of G proteins with guanosine 5'-[gamma-thio]triphosphate or AIF4-. In contrast, the alpha subunits of the stimulatory G protein (Gs alpha) also found associated with the cytoskeletal fraction of unstimulated cells were not released by fMet-Leu-Phe stimulation. However, they were effectively released by direct G-protein activation with guanosine 5'-[gamma-thio]triphosphate. In addition, inhibition of the fMet-Leu-Phe-stimulated modulation of the actin network by pertussis toxin did not affect the fMet-Leu-Phe-induced release of Gn alpha from the cytoskeletal fraction. These observations indicate that fMet-Leu-Phe-induced activation of neutrophils involves a specific dissociation of Gn alpha from the cytoskeleton and that this release is not a consequence of the well-known effect of fMet-Leu-Phe on the cytoskeleton of neutrophils. The present data contribute ideas concerning the transducing properties of G proteins in cellular signaling and seem to reconcile the apparently contradictory concepts of how the cytoskeleton participates in the termination of the chemotactic-factor-induced generation of second messengers in human neutrophils. |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | http://www.pnas.org/content/90/14/6552.full.pdf |
| PubMed reference number | 8341668v1 |
| Volume Number | 90 |
| Issue Number | 14 |
| Journal | Proceedings of the National Academy of Sciences of the United States of America |
| Language | English |
| Access Restriction | Open |
| Subject Keyword | Chemotactic Factors Cytoskeleton Guanosine Diphosphate Guanosine Triphosphate Leucine Ligands Pertussis Toxin Pertussis Vaccine Phenylalanine Plasma membrane fMet-Leu-Phe receptor second messenger |
| Content Type | Text |
| Resource Type | Article |
