Member of GRP1 signaling complexes that are acutely recruited to plasma membrane ruffles in response to insulin receptor signaling. May function as a scaffolding protein that regulates epithelial cell polarity by connecting ARF6 activation with the PAR3 complex. Plays a redundant role with FRMD4A in epithelial polarization. Interacts with CYTH3 (By similarity). Interacts with PARD3 (By similarity). Interacts with CYTH1 (By similarity). Colocalized with PARD3 at adherens junction and tight junction. Extended N-terminus.