Spatial control of Cdc42 signalling by a GM130-RasGRF complex regulates polarity and tumorigenesis

Francesco Baschieri; Stefano Confalonieri; Giovanni Bertalot; Pier Paolo Di Fiore; Wolfgang Dietmaier; Marcel Leist; Piero Crespo; Ian G Macara; Hesso Farhan

doi:10.1038/ncomms5839

Spatial control of Cdc42 signalling by a GM130-RasGRF complex regulates polarity and tumorigenesis

Nat Commun. 2014 Sep 11:5:4839. doi: 10.1038/ncomms5839.

Authors

Francesco Baschieri¹, Stefano Confalonieri², Giovanni Bertalot³, Pier Paolo Di Fiore⁴, Wolfgang Dietmaier⁵, Marcel Leist⁶, Piero Crespo⁷, Ian G Macara⁸, Hesso Farhan¹

Affiliations

¹ 1] University of Konstanz, 78464 Konstanz, Germany [2] Biotechnology Institute Thurgau, University of Konstanz, Kreuzlingen CH-8280, Switzerland.
² 1] Molecular Medicine for Care Program, European Institute of Oncology, Via Ripamonti 435, 20141 Milan, Italy [2] IFOM, Fondazione Istituto FIRC di Oncologia Molecolare, Via Adamello 16, 20139 Milan, Italy.
³ Molecular Medicine for Care Program, European Institute of Oncology, Via Ripamonti 435, 20141 Milan, Italy.
⁴ 1] Molecular Medicine for Care Program, European Institute of Oncology, Via Ripamonti 435, 20141 Milan, Italy [2] IFOM, Fondazione Istituto FIRC di Oncologia Molecolare, Via Adamello 16, 20139 Milan, Italy [3] Dipartimento di Scienze della Salute, Università degli Studi di Milano, Via Antonio di Rudinì 8, 20142 Milan, Italy.
⁵ University of Regensburg, Institute of Pathology and molecular diagnostics, 93053 Regensbur, Germany.
⁶ University of Konstanz, 78464 Konstanz, Germany.
⁷ Instituto de Biomedicina y Biotecnología de Cantabria (IBBTEC), Consejo Superior de Investigaciones Científicas (CSIC)-Universidad de Cantabria-SODERCAN. 39005 Santander, Spain.
⁸ Department of Cell &Developmental Biology, Vanderbilt University, Nashville, Tennessee 37235, USA.

Abstract

The small GTPase Cdc42 is a key regulator of polarity, but little is known in mammals about its spatial regulation and the relevance of spatial Cdc42 pools for polarity. Here we report the identification of a GM130-RasGRF complex as a regulator of Cdc42 at the Golgi. Silencing GM130 results in RasGRF-dependent inhibition of the Golgi pool of Cdc42, but does not affect Cdc42 at the cell surface. Furthermore, active Cdc42 at the Golgi is important to sustain asymmetric front-rear Cdc42-GTP distribution in directionally migrating cells. Concurrent to Cdc42 inhibition, silencing GM130 also results in RasGRF-dependent Ras-ERK pathway activation. Moreover, depletion of GM130 is sufficient to induce E-cadherin downregulation, indicative of a loss in cell polarity and epithelial identity. Accordingly, GM130 expression is frequently lost in colorectal and breast cancer patients. These findings establish a previously unrecognized role for a GM130-RasGRF-Cdc42 connection in regulating polarity and tumorigenesis.

Publication types

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

MeSH terms

Antigens, CD
Autoantigens / genetics*
Autoantigens / metabolism
Cadherins / metabolism
Carcinogenesis / genetics*
Cell Line, Tumor
Cell Polarity / genetics*
Gene Expression Regulation, Neoplastic / genetics*
Gene Silencing
Humans
MAP Kinase Signaling System / physiology
MCF-7 Cells
Membrane Proteins / genetics*
Membrane Proteins / metabolism
Mitogen-Activated Protein Kinase 3 / metabolism
Rho Guanine Nucleotide Exchange Factors / metabolism
Signal Transduction
cdc42 GTP-Binding Protein / genetics*
cdc42 GTP-Binding Protein / metabolism
ras Guanine Nucleotide Exchange Factors / genetics*
ras Guanine Nucleotide Exchange Factors / metabolism
ras-GRF1 / genetics*
ras-GRF1 / metabolism

Substances

Antigens, CD
Autoantigens
CDH1 protein, human
Cadherins
Golgin subfamily A member 2
Membrane Proteins
RASGRF1 protein, human
RASGRF2 protein, human
Rho Guanine Nucleotide Exchange Factors
ras Guanine Nucleotide Exchange Factors
ras-GRF1
Mitogen-Activated Protein Kinase 3
cdc42 GTP-Binding Protein

Grants and funding

R01 GM070902/GM/NIGMS NIH HHS/United States