RUSC2, also known as Iporin, shares with the related protein RUSC1 a common domain structure of RUN, leucine zipper and SH3 domain in addition to over 30 % amino acid identity. RUSC2 is a rab1-interacting protein that also interacts with GM130, another rab1-interacting protein. RUSC2 interacts with specific rab1 isoforms with different rab-binding specificity. It has been suggested that RUSC2 may function as a link between the targeting of ER derived vesicles triggered by the rab1 GTPase and a signaling pathway composed of proteins containing SH3 and/or poly-proline regions.Synonyms: Interacting protein of Rab1, Iporin, KIAA0375, RUN and SH3 domain-containing protein 2