title: BNIP-2 binds phosphatidylserine, localizes to vesicles, and is transported by kinesin-1.
abstract: BNIP-2 shows high homology with the Cayman ataxia protein, caytaxin, which functions as a kinesin-1 adapter bridging cargos and kinesin light chains (KLCs). BNIP-2 is known to induce cell shape changes when over-expressed in culture cells, but its physiological functions are mostly unknown. BNIP-2 interacts with KLC through the conserved WED motif in the N-terminal region of BNIP-2. Interaction with KLC and transportation by kinesin-1 are essential for over-expressed BNIP-2 to elongate cells and induce cellular processes. Endogenous BNIP-2 localizes to the Golgi apparatus, early and recycling endosomes and mitochondria, aligned with microtubules, and moves at a speed compatible with kinesin-1 transportation. The CRAL-TRIO domain of BNIP-2 specifically interacts with phosphatidylserine, and the vesicular localization of BNIP-2 requires interaction with this phospholipid. BNIP-2 mutants which do not bind phosphatidylserine do not induce morphological changes in cells. These data show that similar to caytaxin, BNIP-2 is a kinesin-1 adapter involved in vesicular transportation in the cytoplasm and that association with cargos depends on interaction of the CRAL-TRIO domain with membrane phosphatidylserine.
authors.affiliation: Laboratory of Gene Function in Animals, Nara Institute of Science and Technology, 9816-5 Takayama, Ikoma, Nara, 630-0192, Japan.
authors.forename: Rie
authors.initials: R
authors.lastname: Akamatsu
authors.forename: Norihiro
authors.initials: N
authors.lastname: Ishida-Kitagawa
authors.forename: Takane
authors.initials: T
authors.lastname: Aoyama
authors.forename: Chio
authors.initials: C
authors.lastname: Oka
authors.forename: Masashi
authors.initials: M
authors.lastname: Kawaichi
mesh_terms: D000818:Animals; D019556:COS Cells; D002352:Carrier Proteins / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D002522:Chlorocebus aethiops; D011992:Endosomes / Q000378:metabolism*; D006056:Golgi Apparatus / Q000378:metabolism*; D057809:HEK293 Cells; D006367:HeLa Cells; D006801:Humans; D016547:Kinesins; D008869:Microtubule-Associated Proteins / Q000378:metabolism*; D010718:Phosphatidylserines / Q000378:metabolism*; D011485:Protein Binding
chemical_list: C499184:BNIP2 protein, human; D002352:Carrier Proteins; D008869:Microtubule-Associated Proteins; D010718:Phosphatidylserines; D016547:Kinesins