Novel regulatory mechanisms for the Dbl family guanine nucleotide exchange factor Cool-2/α-Pix
In: The EMBO Journal, Jg. 23 (2004-08-12), S. 3492-3504
Online
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Zugriff:
The Cool-2 (cloned-out of library-2) protein (identical to alpha-Pix for Pak-interactive exchange factor) has been implicated in various biological responses including chemoattractant signaling and in certain forms of mental retardation. We show that when Cool-2 exists as a dimer, it functions as a Rac-specific guanine nucleotide exchange factor (GEF). Dimerization of Cool-2 enables its Dbl (diffuse B-cell lymphoma) and pleckstrin homology domains to work together (in trans) to bind specifically to Rac-GDP. Dissociation of dimeric Cool-2 into its monomeric form allows it to act as a GEF for Cdc42 as well as for Rac. The binding of either PAK (p21-activated kinase) or Cbl (Casitas B-lymphoma) to the SH3 domain of monomeric Cool-2 is necessary for the functional interactions between GDP-bound Cdc42 or Rac and the Cool-2 monomer. The betagamma subunit complex of large GTP-binding proteins, by interacting with PAK, stimulates the dissociation of the Cool-2 dimer and activates its GEF activity for Cdc42. Overall, these findings highlight novel mechanisms by which extracellular signals can direct the specific activation of Rac versus Cdc42 by Cool-2/alpha-Pix.
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Novel regulatory mechanisms for the Dbl family guanine nucleotide exchange factor Cool-2/α-Pix
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Autor/in / Beteiligte Person: | Feng, Qiyu ; Cerione, Richard A. ; Baird, Dan |
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Zeitschrift: | The EMBO Journal, Jg. 23 (2004-08-12), S. 3492-3504 |
Veröffentlichung: | Wiley, 2004 |
Medientyp: | unknown |
ISSN: | 1460-2075 (print) ; 0261-4189 (print) |
DOI: | 10.1038/sj.emboj.7600331 |
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