Inositol 1,4,5-triphosphate-associated cGMP kinase substrate: Basis Sequence: Mouse

Inositol 1, 4, 5-trisphosphate (IP3) receptor associated cyclic GMP (cGMP) kinase substrate (IRAG, also known as Mrv1) is a type-2 integral membrane endoplasmic reticulum (ER) protein, which interacts with IP3 Receptor type 1 (IP3R1), cGMP kinase I-β (cGKI β) and other associated proteins. It plays a key role in NO, cGMP, and cGKI β mediated inhibition of IP3R1 activity and thus relaxes smooth muscle tone and inhibits platelet aggregation. As a scaffolding protein Mrv1 maintains the conformation of a heteroprotein complex containing cGKI β, IP3R1 and other proteins and enables efficient activity of cGKI β within the complex. Increased expression of Mrv1 or IRAG in the absence of tumor related transcription factor in pancreatic cancer cells suggest that it might be involved in tumorigenesis. Downregulation of Mrv1 during megakaryocyte maturation indicates that it is involved in cell growth and differentiation.