The Rac/Cdc42 guanine nucleotide exchange factor beta 1Pix enhances mastoparan-activated Gi-dependent pathway in mast cells

Carbachol stimulates granule exocytosis, phospholipase C (PLC), and phospholipase D (PLD) in RBL-2H3hm1 mast cells by a mechanism that involves G alpha q. However, mastoparan stimulates the same responses through Gi protein. Both Gi and G alpha q pathways are suppressed by Clostridium difficile toxi...

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Bibliographic Details
Published in:Biochemical and biophysical research communications 2004-04, Vol.317 (2), p.384-389
Main Authors: Chahdi, A, Sorokin, A, Dunn, MJ, Landry, Y
Format: Article
Language:English
Subjects:
Clostridium difficile
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Summary:Carbachol stimulates granule exocytosis, phospholipase C (PLC), and phospholipase D (PLD) in RBL-2H3hm1 mast cells by a mechanism that involves G alpha q. However, mastoparan stimulates the same responses through Gi protein. Both Gi and G alpha q pathways are suppressed by Clostridium difficile toxin B, suggesting that Rac and Cdc42 small GTPases are also involved. Over-expression of beta 1Pix, a guanine nucleotide exchange factor for Rac and Cdc42, enhances mastoparan-but not carbachol-induced hexosaminidase secretion and PLC and PLD activation. Furthermore, cells expressing beta 1Pix exhibit elevated levels of mastoparan-stimulated IP3 production. Taken together, these findings implicate beta 1Pix in regulating hexoasaminidase secretion and IP3 production in early stage upon mastoparan stimulation.
ISSN:0006-291X
DOI:10.1016/j.bbrc.2004.03.062