Characterization of Rab45/RASEF containing EF-hand domain and a coiled-coil motif as a self-associating GTPase.
Rab-family GTPases function as key regulators for membrane traffic. Among them, Rab45/RASEF is an atypical GTPase in that it contains a coiled-coil motif at the mid region and a distinct N-terminal EF-hand domain with C-terminal Rab-homology domain. Here, we provide the initial biochemical characterization and intracellular localization of human Rab45. Rab45 bound guanine nucleotide tri- and di-phosphates through the C-terminal Rab domain. Rab45 was capable of self-interacting, and the self-interaction required the mid region containing the coiled-coil motif. Rab45 expressed in HeLa cells was localized in a small patch in the perinuclear area of the cell, and the localization was regulated by the guanine nucleotide-bound states of Rab45. Interestingly, the mid region, together with Rab domain, appeared to be essential for the characteristic perinuclear localization of Rab45, indicating that the self-interaction may be involved in the intracellular localization of Rab45.
Shintani
Mami
M
Department of Physiological Chemistry, Graduate School of Pharmaceutical Sciences, University of Tokyo, 7-3-1 Hongo, Tokyo 113-0033, Japan.
Tada
Minoru
M
Kobayashi
Tetsuo
T
Kajiho
Hiroaki
H
Kontani
Kenji
K
Katada
Toshiaki
T
D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D001665:Binding Sites; D002460:Cell Line; D020558:GTP Phosphohydrolases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D006150:Guanine Nucleotides / Q000378:metabolism; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D018613:Microscopy, Confocal; D009154:Mutation; D011485:Protein Binding; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D014162:Transfection
D006150:Guanine Nucleotides; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D020558:GTP Phosphohydrolases