Scaffolding protein that regulates epithelial cell polarity by connecting ARF6 activation with the PAR3 complex (PubMed:20080746). Plays a redundant role with FRMD4B in epithelial polarization (PubMed:20080746). May regulate MAPT secretion by activating ARF6-signaling (By similarity). Interacts (via coiled-coil domain) with CYTH1 (via coiled-coil domain) (PubMed:20080746). Interacts with PARD3 (via coiled-coil domain) (PubMed:20080746). Found in a complex with PARD3, CYTH1 and FRMD4A (PubMed:20080746). Interacts with CYTH2 (PubMed:20080746). Interacts with CYTH3 (PubMed:20080746). Colocalized with CYTH1 at adherens junction and tight junction (PubMed:20080746). Colocalized with PARD3 during the process of epithelial polarization (PubMed:20080746).