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Publication Abstract from PubMed

Phosphatidylinositol 3,4,5-triphosphate (PIP3) plays a key role in neuronal polarization and axon formation. PIP3-containing vesicles are transported to axon tips by the kinesin KIF13B via an adaptor protein, centaurin alpha1 (CENTA1). KIF13B interacts with CENTA1 through its forkhead-associated (FHA) domain. We solved the crystal structures of CENTA1 in ligand-free, KIF13B-FHA domain-bound, and PIP3 head group (IP4)-bound conformations, and the CENTA1/KIF13B-FHA/IP4 ternary complex. The first pleckstrin homology (PH) domain of CENTA1 specifically binds to PIP3, while the second binds to both PIP3 and phosphatidylinositol 3,4-biphosphate (PI(3,4)P(2)). The FHA domain of KIF13B interacts with the PH1 domain of one CENTA1 molecule and the ArfGAP domain of a second CENTA1 molecule in a threonine phosphorylation-independent fashion. We propose that full-length KIF13B and CENTA1 form heterotetramers that can bind four phosphoinositide molecules in the vesicle and transport it along the microtubule.

Phosphorylation-independent dual-site binding of the FHA domain of KIF13 mediates phosphoinositide transport via centaurin {alpha}1.,Tong Y, Tempel W, Wang H, Yamada K, Shen L, Senisterra GA, Mackenzie F, Chishti AH, Park HW Proc Natl Acad Sci U S A. 2010 Nov 5. PMID:21057110^[3]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.