Mechanistic insight into GPCR-mediated activation of the microtubule-associated RhoA exchange factor GEF-H1

David Meiri; Christopher B Marshall; Daphna Mokady; Jose LaRose; Michael Mullin; Anne-Claude Gingras; Mitsuhiko Ikura; Robert Rottapel

doi:10.1038/ncomms5857

Mechanistic insight into GPCR-mediated activation of the microtubule-associated RhoA exchange factor GEF-H1

Nat Commun. 2014 Sep 11:5:4857. doi: 10.1038/ncomms5857.

Authors

David Meiri¹, Christopher B Marshall², Daphna Mokady², Jose LaRose², Michael Mullin³, Anne-Claude Gingras⁴, Mitsuhiko Ikura⁵, Robert Rottapel⁶

Affiliations

¹ Department of Biology, Technion Israel Institute of Technology, Haifa 32000, Israel.
² Princess Margaret Cancer Centre, University Health Network, University of Toronto, 101 College Street, Room 12-704, Toronto Medical Discovery Tower, Toronto, Ontario, Canada M5G 1L7.
³ Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, 600 University Avenue, Room 992A, Toronto, Ontario, Canada M5G 1X5.
⁴ 1] Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, 600 University Avenue, Room 992A, Toronto, Ontario, Canada M5G 1X5 [2] Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada M5S 1A8.
⁵ 1] Princess Margaret Cancer Centre, University Health Network, University of Toronto, 101 College Street, Room 12-704, Toronto Medical Discovery Tower, Toronto, Ontario, Canada M5G 1L7 [2] Department of Medical Biophysics, University of Toronto, 1 King's College Circle, Toronto, Ontario, Canada M5S 1A8.
⁶ 1] Princess Margaret Cancer Centre, University Health Network, University of Toronto, 101 College Street, Room 12-704, Toronto Medical Discovery Tower, Toronto, Ontario, Canada M5G 1L7 [2] Department of Medical Biophysics, University of Toronto, 1 King's College Circle, Toronto, Ontario, Canada M5S 1A8 [3] Department of Medicine, University of Toronto, 1 King's College Circle, Toronto, Ontario, Canada M5S 1A8 [4] Department of Immunology, University of Toronto, 1 King's College Circle, Toronto, Ontario, Canada M5S 1A8 [5] Division of Rheumatology, St Michael's Hospital, 30 Bond Street, Toronto, Ontario, Canada M5B 1W8.

PMID: 25209408
DOI: 10.1038/ncomms5857

Abstract

The RhoGEF GEF-H1 can be sequestered in an inactive state on polymerized microtubules by the dynein motor light-chain Tctex-1. Phosphorylation of GEF-H1 Ser885 by PKA or PAK kinases creates an inhibitory 14-3-3-binding site. Here we show a new mode of GEF-H1 activation in response to the G-protein-coupled receptor (GPCR) ligands lysophosphatidic acid (LPA) or thrombin that is independent of microtubule depolymerization. LPA/thrombin stimulates disassembly of the GEF-H1:dynein multi-protein complex through the concerted action of Gα and Gβγ. Gα binds directly to GEF-H1 and displaces it from Tctex-1, while Gβγ binds to Tctex-1 and disrupts its interaction with the dynein intermediate chain, resulting in the release of GEF-H1. Full activation of GEF-H1 requires dephosphorylation of Ser885 by PP2A, which is induced by thrombin. The coordinated displacement of GEF-H1 from microtubules by G-proteins and its dephosphorylation by PP2A demonstrate a multistep GEF-H1 activation and present a unique mechanism coupling GPCR signalling to Rho activation.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

14-3-3 Proteins / metabolism
Animals
Dyneins / metabolism*
GTP-Binding Protein alpha Subunits, G12-G13 / drug effects
GTP-Binding Protein alpha Subunits, G12-G13 / metabolism
GTP-Binding Protein beta Subunits / drug effects
GTP-Binding Protein beta Subunits / metabolism
GTP-Binding Protein gamma Subunits / drug effects
GTP-Binding Protein gamma Subunits / metabolism
Lysophospholipids / pharmacology
Mice
Mice, Knockout
Microtubules / metabolism*
Phosphorylation
Receptors, G-Protein-Coupled / drug effects
Receptors, G-Protein-Coupled / metabolism*
Rho Guanine Nucleotide Exchange Factors / drug effects
Rho Guanine Nucleotide Exchange Factors / metabolism*
Thrombin / pharmacology
p21-Activated Kinases / metabolism

Substances

14-3-3 Proteins
Arhgef2 protein, mouse
Dynlt1b protein, mouse
GTP-Binding Protein beta Subunits
GTP-Binding Protein gamma Subunits
Lysophospholipids
Receptors, G-Protein-Coupled
Rho Guanine Nucleotide Exchange Factors
p21-Activated Kinases
Thrombin
Dyneins
GTP-Binding Protein alpha Subunits, G12-G13
lysophosphatidic acid

Grants and funding

MOP-84314/Canadian Institutes of Health Research/Canada