In model species such as the yeast Saccharomyces cerevisiae, the primate Homo sapiens (See RANGAP1) and the plant Arabidopsis thaliana, it acts as a GTPase-activating protein, catalysing the conversion of cytosolically-bound RanGTP to RanGDP.
It has the opposite function of the RCC1, a nuclear-located protein that converts RanGDP to RanGTP.
In mammalian and plant cells, RanGAP is located at the nuclear envelope during interphase.
[2] In contrast to plant and animal cells, yeast RanGAP is located in the cytosol.
[3] Together with RCC1 and components of the nuclear pore, RanGAP has been suggested to have evolved at the origin of eukaryotes.