The protein encoded by this gene is a nuclear import receptor for serine/arginine-rich (SR) proteins such as the splicing factors SFRS1 and SFRS2. The encoded protein has also been shown to be involved in HIV-1 infection, apparently through interaction with the HIV-1 capsid protein. Two transcript variants encoding different isoforms as well as a noncoding transcript have been found for this gene.[provided by RefSeq, Jul 2010].