Inhibitory and stimulatory regulation of Rac and cell motility by the G12/13-Rho and Gi pathways integrated downstream of a single G protein-coupled sphingosine-1-phosphate receptor isoform
Inhibitory and stimulatory regulation of Rac and cell motility by the G12/13-Rho and Gi pathways integrated downstream of a single G protein-coupled sphingosine-1-phosphate receptor isoform
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DOI：
10.1128/mcb.23.5.1534-1545.2003
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发表时间：
2003-03-01
影响因子：
5.3
通讯作者：
Takuwa, Y
中科院分区：
文献类型：
--
作者：
Sugimoto, N;Takuwa, N;Takuwa, Y
G蛋白偶联受体S1P(2)/Edg5和S1P(3)/Edg3均介导鞘鞘醇- i -磷酸（SIP）刺激Rho，但S1P(2)而非S1P(3)介导Rac激活、膜皱缩和细胞迁移的下调，以响应化学引诱剂。通过表达各自的c端肽，可以特异性抑制内源性Galpha（12）和Galpha(13)，但不抑制Galpha(q)，从而消除S1P(2)介导的Rac、膜褶皱和迁移的抑制，以及刺激Rho和应激纤维的形成。融合受体包括S1P(2)和Galpha（12）或Galpha(13)，但不包括Galpha(q)，介导SIP刺激Rho，也抑制Rac和迁移。相比之下，过度表达Galpha(j)特异性地拮抗S1P(2)介导的Rac和迁移抑制。S1P(2)的作用被V(14)Rho的表达模仿，并被C3毒素和N(19)Rho所消除，但不被Rho激酶抑制剂所消除。与S1P(2)相反，S1P(3)介导S1P导向的百日咳毒素敏感趋化和Rac激活，尽管Rho通过G同时刺激（12/13）。在G(i)被百日咳毒素灭活后，S1P(3)与S1P(2)一样介导了Rac和迁移的抑制。这些结果表明，来自G(i)-和G(12/13)- rho通路的抵消信号的整合指导Rac的正调控或负调控，从而在激活单个SIP受体异构体时进行细胞迁移。
The G protein-coupled receptors S1P(2)/Edg5 and S1P(3)/Edg3 both mediate sphingosine-I-phosphate (SIP) stimulation of Rho, yet S1P(2) but not S1P(3) mediates downregulation of Rac activation, membrane ruffling, and cell migration in response to chemoattractants. Specific inhibition of endogenous Galpha(12) and Galpha(13), but not of Galpha(q) by expression of respective C-terminal peptides abolished S1P(2)-mediated inhibition of Rac, membrane ruffling, and migration, as well as stimulation of Rho and stress fiber formation. Fusion receptors comprising S1P(2) and either Galpha(12) or Galpha(13), but not Galpha(q), mediated SIP stimulation of Rho and also inhibition of Rac and migration. Overexpression of Galpha(j), by contrast, specifically antagonized S1P(2)-mediated inhibition of Rac and migration. The S1P(2) actions were mimicked by expression of V(14)Rho and were abolished by C3 toxin and N(19)Rho, but not Rho kinase inhibitors. In contrast to S1P(2), S1P(3) mediated S1P-directed, pertussis toxin-sensitive chemotaxis and Rac activation despite concurrent stimulation of Rho via G(12/13). Upon inactivation of G(i) by pertussis toxin, S1P(3) mediated inhibition of Rac and migration just like S1P(2). These results indicate that integration of counteracting signals from the G(i)- and the G(12/13)-Rho pathways directs either positive or negative regulation of Rac, and thus cell migration, upon activation of a single SIP receptor isoform.