Stable Isotopic Labeling (SILAC) in the MS Analysis of Cortactin Binding Partners

JAY W. FOX; PABLO R. GRIGERA; NICHOLAS SHERMAN; LI MA; KRISTINA NELSON; J. TOM PARSONS;

Long Beach , California, USA

Congreso; HUPO 5th Annual World Congress; 2006

Human Proteome Organization

  By coupling M2 agarose purification, in vivo isotopic labeling and MS, we have identified 33 putative  intracellular binding partners of cortactin.  In addition to ARP-complex related proteins and dynamin, well known partners of cortactin, we also identified proteins like RCC2 (a likely Ras-GEF), Rec8, septin and TABP (a nuclear and cytoplasmic  protein that colocalizes with cortical actin) that suggest a possible interaction of cortactin with the cytokinetic apparatus of the cell.  Also present were scinderin (an actin filament severing protein) and MTMR1 (a PH domain-containing tyrosine phosphatase that induces oncogenic transformation in fibroblasts).  Both the diversity and characteristics of the proteins detected in this study give support to recent hypotheses that have provocatively linked mitosis with cell migration (i.e., McHugh et al, J. Cell Biol. (2004) 167:673-686).  Experiments to validate  these interactions are currently underway.