MYOZAP, also known as GRINL1A, is a 54 kDa highly conserved cardiac protein. It is strongly expressed in the heart and lung and is a novel component of intercalated disc. MYOZAP interacts with myosin phosphatase-RhoA interacting protein (MRIP) and acts as an activator of Rho-dependent SRF signaling. Knockdown study in zebrafish results in cardiomyopathy with severe dysfunction. The MYOZAP gene is part of a complex transcript unit that includes the gene for glutamate receptor, ionotropic, N-methyl D-aspartate-like 1A (GRINL1A). Transcription of this gene occurs at an upstream promoter, with two different groups of alternatively spliced variants: Gup for GRINL1A upstream transcripts and Gcom for GRINL1A combined transcripts.