The Rho GTPase Rif signals through IRTKS, Eps8 and WAVE2 to generate dorsal membrane ruffles and filopodia.
Rif induces dorsal filopodia but the signaling pathway responsible for this has not been identified. We show here that Rif interacts with the I-BAR family protein IRTKS (also known as BAIAP2L1) through its I-BAR domain. Rif also interacts with Pinkbar (also known as BAIAP2L2) in N1E-115 mouse neuroblastoma cells. IRTKS and Rif induce dorsal membrane ruffles and filopodia. Dominant-negative Rif inhibits the formation of IRTKS-induced morphological structures, and Rif activity is blocked in IRTKS-knockout (KO) cells. To further define the Rif-IRTKS signaling pathway, we identify Eps8 and WAVE2 (also known as WASF2) as IRTKS interactors. We find that Eps8 regulates the size and number of dorsal filopodia and membrane ruffles downstream of Rif-IRTKS signaling, whereas WAVE2 modulates dorsal membrane ruffling. Furthermore, our data suggests that Tir, a protein essential for enterohemorrhagic Escherichia coli infection, might compete for Rif for interaction with the I-BAR domain of IRTKS. Based on this evidence, we propose a model in which Rho family GTPases use the I-BAR proteins, IRSp53 (also known as BAIAP2), IRTKS and Pinkbar, as a central mechanism to modulate cell morphology.
Neural Stem Cell Laboratory, Institute of Medical Biology, 8A Biomedical Grove, Immunos, 138648 Singapore.
Thankiah
T
Sudhaharan
Neural Stem Cell Laboratory, Institute of Medical Biology, 8A Biomedical Grove, Immunos, 138648 Singapore.
Kai Ping
KP
Sem
Neural Stem Cell Laboratory, Institute of Medical Biology, 8A Biomedical Grove, Immunos, 138648 Singapore.
Hwi Fen
HF
Liew
Neural Stem Cell Laboratory, Institute of Medical Biology, 8A Biomedical Grove, Immunos, 138648 Singapore.
Yuan Hong
YH
Yu
Neural Stem Cell Laboratory, Institute of Medical Biology, 8A Biomedical Grove, Immunos, 138648 Singapore Mechanobiology Institute, National University of Singapore, 5A Engineering Drive 1, 117411 Singapore.
Wah Ing
WI
Goh
Neural Stem Cell Laboratory, Institute of Medical Biology, 8A Biomedical Grove, Immunos, 138648 Singapore.
Ai Mei
AM
Chou
Neural Stem Cell Laboratory, Institute of Medical Biology, 8A Biomedical Grove, Immunos, 138648 Singapore sohail.ahmed@imb.a-star.edu.sg.
Sohail
0000-0002-5208-8193
S
Ahmed
D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism*; D000818:Animals; D020558:GTP Phosphohydrolases / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D051379:Mice; D008840:Microfilament Proteins / Q000378:metabolism*; D008954:Models, Biological; D041681:NIH 3T3 Cells; D011485:Protein Binding; D011554:Pseudopodia / Q000378:metabolism*; D015398:Signal Transduction; D051300:Wiskott-Aldrich Syndrome Protein Family / Q000378:metabolism*
D048868:Adaptor Proteins, Signal Transducing; C523100:BAIAP2L1 protein, human; C000606831:IRTKS protein, mouse; D008840:Microfilament Proteins; D051300:Wiskott-Aldrich Syndrome Protein Family; D020558:GTP Phosphohydrolases
Dorsal filopodia; Dorsal ruffles; Eps8; IRTKS; WAVE2