Plays a role in cellular signaling via Rho-related GTP-binding proteins and activation of transcription factor SRF. Targets TJP1 to cell junctions (By similarity). In cortical neurons, may play a role in glutaminergic signal transduction through interaction with the NMDA receptor subunit GRIN1. Interacts with DSP, MPRIP and TJP1/ZO1. Interaction with MPRIP inhibits the activation of transcription factor SRF (By similarity). Interacts with GRIN1. Interacts with DYNLL1 (By similarity). Detected predominantly at the intercalated disk in cardiomyocytes, and at low levels on sarcomeric Z disKs. Colocalizes with F-actin. Colocalizes with cortical actin (PubMed:20093627). In neurons, colocalizes with GRIN1 in postsynaptic neurites (PubMed:18849881). In heart, localizes at area composita, the mixed-type junctional structure composed of both desmosomal and adherens junctional proteins (PubMed:31384490). Detected in brain, heart and lung (at protein level) (PubMed:31384490). Expressed in optic nerve sheath envelope(at protein level) (PubMed:29445566). Belongs to the MYZAP family.