RAN Binding Protein 3 (RANBP3)

The RAN GTPase plays an essential role in the transport of macromolecules between the cytoplasm and the nucleus. The nucleotide-bound state of RAN is regulated by RANGAP1, a RAN-specific GTPase activating protein, and by RCC1 (CHC1), a specific guanine nucleotide exchange factor.

RANBP3 encodes a protein with a RanBD1 domain that is found in both the nucleus and cytoplasm. This protein plays a role in nuclear export as part of a heteromeric complex. Alternate transcriptional splice variants, encoding different isoforms, have been characterized.RANBP3 formed a trimeric RCC1-RAN-RANBP3 complex, although it did not bind RCC1 directly. Northern blot analysis revealed that RANBP3 is expressed ubiquitously as 1.8- and 3-kb mRNAs.