Structure of transportin SR2, a karyopherin involved in human disease, in complex with Ran

Transportin SR2 (TRN-SR2) is a β-type karyopherin responsible for the nuclear import of specific cargoes, including serine/arginine-rich splicing factors. The protein has been implicated in a variety of human diseases, including HIV infection, primary biliary cirrhosis and limb-girdle muscular dystrophy 1F. Towards understanding its molecular mechanism, a 2.9 Å resolution crystal structure of human TRN-SR2 complexed with the small GTPase Ran has been determined. TRN-SR2 is composed of 20 α-helical HEAT repeats forming a solenoid-like fold. The first nine repeats form a `cradle' for the binding of RanGTP, revealing similarities but also differences with respect to the related importin 13 complex.

Source: Acta Crystallographica Section F - May 24, 2014 Category: Biochemistry Authors: Tsirkone, V.G.Beutels, K.G.Demeulemeester, J.Debyser, Z.Christ, F.Strelkov, S.V. Tags: nuclear import molecular mechanism transportin SR2 structural communications Source Type: research