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Free keywords:
INTRAFLAGELLAR TRANSPORT IFT; TRANSITION ZONE; CELLS ANTENNA; B CORE;
PROTEIN; CILIUM; GTPASES; CILIOPATHIES; CILIOGENESIS; MECHANISMScilium; flagellum; intraflagellar transport; GTPase; RabGAP;
Tre2-Bub2-Cdc16 domain;
Abstract:
Rab GTPases play a crucial role in the regulation of many intracellular membrane trafficking pathways including endo sis and ciliogenesis. Rat) GTPase activating proteins (RabGAPs) inc the GTP hydrolysis rate of Rah GTPases an d them into guanine nucleotide diphosphate (GDP) bound inactive form. th Here, we determined the crystal structure of e putative catalytic domain of a RabGAP (which we name CrfRabGAP) that is found in the flagellar proteorne of the unicellular green alga Chinmydomonas reinhardtii. BLAST searches revealed potential human orthologues of CrfRabGAP as TBC1D3 and TBC1D26. Sequence and structural comparison with other canonical RabGAPs revealed that the CrfRabGAP does not contain the canonical catalytic residues required for the activation of Rah GTPases. The function of noncanonical RahGAPslike CrfRabGAP might be to serve as Rah effectors rather than activators.
