May regulate the intracellular trafficking of RAN (PubMed:10811801, PubMed:11733047). Promotes guanine nucleotide release from RAN and inhibits binding of new GTP by preventing the binding of the RAN guanine nucleotide exchange factor RCC1 (PubMed:10811801, PubMed:11733047). Regulates the levels of GTP-bound RAN in the nucleus, and thereby plays a role in the regulation of RAN-dependent mitotic spindle dynamics (By similarity). Enhances the expression of SCN5A at the cell membrane in cardiomyocytes (PubMed:18184654, PubMed:23420830). Monomer (Probable). Interacts with RAN, both RAN-GTP and RAN-GDP (PubMed:10811801). Competes with RCC1 for a common binding site on RAN and thereby inhibits RCC1-mediated nucleotide exchange (By similarity). Forms a complex with RAN-GTP and RANBP1 (PubMed:10811801). Interacts with the cytoplasmic loop 2 of SCN5A (PubMed:18184654). Shuttles between the nucleus and cytoplasm. Highgly abundant in cardiac cells. Expressed in testis during prepubertal development. Down-regulated in mice lacking Ovol1. Belongs to the MOG1 family.