title: The calcium-sensing receptor changes cell shape via a beta-arrestin-1 ARNO ARF6 ELMO protein network.
abstract: G-protein-coupled receptors (GPCRs) transduce the binding of extracellular stimuli into intracellular signalling cascades that can lead to morphological changes. Here, we demonstrate that stimulation of the calcium-sensing receptor (CaSR), a GPCR that promotes chemotaxis by detecting increases in extracellular calcium, triggers plasma membrane (PM) ruffling via a pathway that involves beta-arrestin 1, Arf nucleotide binding site opener (ARNO), ADP-ribosylating factor 6 (ARF6) and engulfment and cell motility protein (ELMO). Expression of dominant negative beta-arrestin 1 or its knockdown with siRNA impaired the CaSR-induced PM ruffling response. Expression of a catalytically inactive ARNO also reduced CaSR-induced PM ruffling. Furthermore, beta-arrestin 1 co-immunoprecipitated with the CaSR and ARNO under resting conditions. Agonist treatment did not markedly alter beta-arrestin 1 binding to the CaSR or to ARNO but it did elicit the translocation and colocalisation of the CaSR, beta-arrestin 1 and ARNO to membrane protrusions. Furthermore, ARF6 and ELMO, two proteins known to couple ARNO to the cytoskeleton, were required for CaSR-dependent morphological changes and translocated to the PM ruffles. These data suggest that cells ruffle upon CaSR stimulation via a mechanism that involves translocation of beta-arrestin 1 pre-assembled with the CaSR or ARNO, and that ELMO plays an essential role in this CaSR-signalling-induced cytoskeletal reorganisation.
authors.affiliation: Department of Anatomy, MRC Centre for Synaptic Plasticity, University of Bristol, University Walk, Bristol, BS8 1TD, UK.
authors.forename: Tristan
authors.initials: T
authors.lastname: Bouschet
authors.forename: Stéphane
authors.initials: S
authors.lastname: Martin
authors.forename: Venkateswarlu
authors.initials: V
authors.lastname: Kanamarlapudi
authors.forename: Stuart
authors.initials: S
authors.lastname: Mundell
authors.forename: Jeremy M
authors.initials: JM
authors.lastname: Henley
mesh_terms: D000089982:ADP-Ribosylation Factor 6; D020727:ADP-Ribosylation Factors / Q000302:isolation & purification / Q000378:metabolism*; D000199:Actins / Q000302:isolation & purification / Q000378:metabolism; D048868:Adaptor Proteins, Signal Transducing / Q000302:isolation & purification / Q000378:metabolism*; D019390:Arrestins / Q000302:isolation & purification / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism*; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D002465:Cell Movement / Q000502:physiology; D048430:Cell Shape; D020690:GTPase-Activating Proteins / Q000302:isolation & purification / Q000378:metabolism*; D006801:Humans; D044169:Receptors, Calcium-Sensing / Q000302:isolation & purification / Q000378:metabolism*; D000071559:beta-Arrestin 1; D000071557:beta-Arrestins
chemical_list: D000089982:ADP-Ribosylation Factor 6; C000605253:ARRB1 protein, human; D000199:Actins; D048868:Adaptor Proteins, Signal Transducing; D019390:Arrestins; C465214:ELMO1 protein, human; D020690:GTPase-Activating Proteins; D044169:Receptors, Calcium-Sensing; D000071559:beta-Arrestin 1; D000071557:beta-Arrestins; C102474:cytohesin-2; D020727:ADP-Ribosylation Factors; C000715348:ARF6 protein, human; D002118:Calcium