A role for POR1, a Rac1-interacting protein, in ARF6-mediated cytoskeletal rearrangements

D’Souza‐Schorey, Crislyn; Boshans, Rita L.; McDonough, Michele; Stahl, Philip D.; Aelst, Linda Van

doi:10.1093/emboj/16.17.5445

Cited by 224 publications

(206 citation statements)

References 48 publications

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“…GLUT4 translocation (41), to participate in regulated exocytosis by activating phospholipase D (17,38), to play a regulatory role in receptor-mediated endocytosis (39), to remodel the actin cytoskeleton (34,42), and to be required for phagocytosis in macrophage (43). Our results show that Arf6 also participates in GPCR desensitization.…”

Section: Discussionmentioning

confidence: 75%

The ADP ribosylation factor nucleotide exchange factor ARNO promotes β-arrestin release necessary for luteinizing hormone/choriogonadotropin receptor desensitization

Mukherjee

Gurevich

Jones

et al. 2000

Proc. Natl. Acad. Sci. U.S.A.

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Desensitization of guanine nucleotide binding protein-coupled receptors is a ubiquitous phenomenon characterized by declining effector activity upon persistent agonist stimulation. The luteinizing hormone/choriogonadotropin receptor (LH/CGR) in ovarian follicles exhibits desensitization of effector adenylyl cyclase activity in response to the mid-cycle surge of LH. We have previously shown that uncoupling of the agonist-activated LH/CGR from the stimulatory G protein (G s) is dependent on GTP and attributable to binding of ␤-arrestin present in adenylyl cyclase-rich follicular membrane fraction to the third intracellular (3i) loop of the receptor. Here, we report that LH/CGR-dependent desensitization is mimicked by ADP ribosylation factor nucleotide-binding site opener, a guanine nucleotide exchange factor of the small G proteins ADP ribosylation factors (Arfs) 1 and 6, and blocked by synthetic N-terminal Arf6 peptide, suggesting that the GTP-dependent step of LH/CGR desensitization is receptor-dependent Arf6 activation. Arf activation by GTP and ADP ribosylation factor nucelotide-binding site opener promotes the release of docked ␤-arrestin from the membrane, making ␤-arrestin available for LH/CGR; Arf6 but not Arf1 peptides block ␤-arrestin release from the membrane. Thus, LH/CGR appears to activate two membrane delimited signaling cascades via two types of G proteins: heterotrimeric Gs and small G protein Arf6. Arf6 activation releases docked ␤-arrestin necessary for receptor desensitization, providing a feedback mechanism for receptor self-regulation.T he luteinizing hormone/choriogonadotropin receptor (LH/ CGR) belongs to the seven transmembrane family of receptors that signal by the activation of guanine nucleotide binding (G) proteins and downstream effectors including adenylyl cyclase (AC) (1-4). Characteristic of virtually all G proteincoupled receptors (GPCRs) (5), LH-and human (h) CG-stimulated AC activities wane in response to persistent stimulation of the LH/CGR by saturating agonist concentrations (6-8). We have previously shown that desensitization of the endogenous ovarian follicular LH/CGR in a cell-free membrane model is GTP dependent (K m Ϸ70 nM) (9-11). Based on the ability of anti-arrestin antibodies to abrogate LH/CGR desensitization, we concluded that endogenous plasma membranebound ␤-arrestin mediates desensitization of the follicular LH/ CGR (12). Using synthetic peptides, we have also shown that on LH/CGR activation, ␤-arrestin specifically binds to the 3i loop of the activated LH/CGR, blocking its interaction with G s (13). Here, we investigate the molecular basis of the GTP dependence of LH/CGR desensitization and the mechanism of the release of the membrane-bound ␤-arrestin required for LH/CGR desensitization. Materials and MethodsMaterials. , ADP ribosylation factor (Arf) nucleotide-binding site opener (ARNO) and ARNO mutant proteins (15), and Clostridium difficile and Clostridium sordelli toxins (16) were expressed and purified as described. Myristoylated (Myr)-Arf6(2-13), non-Myr-...

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Section: Discussionmentioning

confidence: 75%

The ADP ribosylation factor nucleotide exchange factor ARNO promotes β-arrestin release necessary for luteinizing hormone/choriogonadotropin receptor desensitization

Mukherjee

Gurevich

Jones

et al. 2000

Proc. Natl. Acad. Sci. U.S.A.

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“…However, Arf and Rho family proteins could interact in other ways as well. For instance, Arf could affect the trafficking of Rac (16), or Rho and Arf could together affect the activity of a common protein, such as Partner of Rac (11,59), PtdIns4P 5 kinase (60), or phospholipase D (58). Alternatively, Arf and Rho proteins could reciprocally affect each other's activation or inactivation.…”

Section: Discussionmentioning

confidence: 99%

“…However, they are also involved in remodeling the actin cytoskeleton as cells change shape or move. Thus, Arf6 affects endocytosis and phagocytosis, but also regulates the polymerization of cortical actin and cell spreading (9)(10)(11)(12)(13)(14)(15)(16). Arf1 regulates function of the Golgi, endoplasmic reticulum-to-Golgi transport, and recruitment of transport vesicle coat proteins COPI, AP-1, and AP-3, but also affects the recruitment of paxillin to FAs (17)(18)(19)(20)(21)(22).…”

mentioning

confidence: 99%

The Arf GTPase-activating protein ASAP1 regulates the actin cytoskeleton

Randazzo

Andrade

Miura

et al. 2000

Proc. Natl. Acad. Sci. U.S.A.

204

182

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Arf family GTP-binding proteins are best characterized as regulators of membrane traffic, but recent studies indicate an additional role in cytoskeletal organization. An Arf GTPase-activating protein of the centaurin ␤ family, ASAP1 (also known as centaurin ␤4), binds Arf and two other known regulators of the actin cytoskeleton, the tyrosine kinase Src and phosphatidylinositol 4,5-bisphosphate. In this paper, we show that ASAP1 localizes to focal adhesions and cycles with focal adhesion proteins when cells are stimulated to move. Overexpression of ASAP1 altered the morphology of focal adhesions and blocked both cell spreading and formation of dorsal ruffles induced by platelet-derived growth factor (PDGF). On the other hand, ASAP1, with a mutation that disrupted GTPase-activating protein activity, had a reduced effect on cell spreading and increased the number of cells forming dorsal ruffles in response to PDGF. These data support a role for an Arf GTPase-activating protein, ASAP1, as a regulator of cytoskeletal remodeling and raise the possibility that the Arf pathway is a target for PDGF signaling.

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“…Previous studies have suggested a role for ARF6 in regulating Rac1 activity (D'Souza-Schorey et al, 1997;Radhakrishna et al, 1999;Zhang et al, 1999). In an attempt to determine if, in our model system, ARF6 is required for Rac1 activation, we initially investigated whether ARF6 and Rac can associate in an agonist-dependent manner.…”

Section: Ang II Stimulation Promotes the Activation Of Endogenous Arfmentioning

confidence: 99%

Endogenous ARF6 Interacts with Rac1 upon Angiotensin II Stimulation to Regulate Membrane Ruffling and Cell Migration

Cotton

Boulay

Houndolo

et al. 2007

MBoC

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ARF6 and Rac1 are small GTPases known to regulate remodelling of the actin cytoskeleton. Here, we demonstrate that these monomeric G proteins are sequentially activated when HEK 293 cells expressing the angiotensin type 1 receptor (AT 1 R) are stimulated with angiotensin II (Ang II). After receptor activation, ARF6 and Rac1 transiently form a complex. Their association is, at least in part, direct and dependent on the nature of the nucleotide bound to both small G proteins. ARF6-GTP preferentially interacts with Rac1-GDP. AT 1 R expressing HEK293 cells ruffle, form membrane protrusions, and migrate in response to agonist treatment. ARF6, but not ARF1, depletion using small interfering RNAs recapitulates the ruffling and migratory phenotype observed after Ang II treatment. These results suggest that ARF6 depletion or Ang II treatment are functionally equivalent and point to a role for endogenous ARF6 as an inhibitor of Rac1 activity. Taken together, our findings reveal a novel function of endogenously expressed ARF6 and demonstrate that by interacting with Rac1, this small GTPase is a central regulator of the signaling pathways leading to actin remodeling.

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A role for POR1, a Rac1-interacting protein, in ARF6-mediated cytoskeletal rearrangements

Cited by 224 publications

References 48 publications

The ADP ribosylation factor nucleotide exchange factor ARNO promotes β-arrestin release necessary for luteinizing hormone/choriogonadotropin receptor desensitization

The ADP ribosylation factor nucleotide exchange factor ARNO promotes β-arrestin release necessary for luteinizing hormone/choriogonadotropin receptor desensitization

The Arf GTPase-activating protein ASAP1 regulates the actin cytoskeleton

Endogenous ARF6 Interacts with Rac1 upon Angiotensin II Stimulation to Regulate Membrane Ruffling and Cell Migration

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