Interaction of POB1, a downstream molecule of small G protein Ral, with PAG2, a paxillin-binding protein, is involved in cell migration.
POB1 was previously identified as a RalBP1-binding protein. POB1 and RalBP1 function downstream of small G protein Ral and regulate receptor-mediated endocytosis. To look for additional functions of POB1, we screened for POB1-binding proteins using a yeast two-hybrid method and found that POB1 interacts with mouse ASAP1, which is a human PAG2 homolog. PAG2 is a paxillin-associated protein with ADP-ribosylation factor GTPase-activating protein activity. POB1 formed a complex with PAG2 in intact cells. The carboxyl-terminal region containing the proline-rich motifs of POB1 directly bound to the carboxyl-terminal region including the SH3 domain of PAG2. Substitutions of Pro(423) and Pro(426) with Ala (POB1(PA)) impaired the binding of POB1 to PAG2. Expression of PAG2 inhibited fibronectin-dependent migration and paxillin recruitment to focal contacts of CHO-IR cells. Co-expression with POB1 but not with POB1(PA) suppressed the inhibitory action of PAG2 on cell migration and paxillin localization. These results suggest that POB1 interacts with PAG2 through its proline-rich motif, thereby regulating cell migration.
Oshiro
Takafumi
T
Department of Biochemistry, Graduate School of Biomedical Sciences, Hiroshima University, 1-2-3, Kasumi, Minami-ku, Hiroshima 734-8551, Japan.
Koyama
Shinya
S
Sugiyama
Shinichiro
S
Kondo
Akiko
A
Onodera
Yasuhito
Y
Asahara
Toshimasa
T
Sabe
Hisataka
H
Kikuchi
Akira
A
D048868:Adaptor Proteins, Signal Transducing; D020816:Amino Acid Motifs; D000818:Animals; D002135:Calcium-Binding Proteins; D002352:Carrier Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D002465:Cell Movement / Q000502:physiology*; D003598:Cytoskeletal Proteins / Q000235:genetics / Q000378:metabolism; D022001:Focal Adhesions; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D020690:GTPase-Activating Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017930:Genes, Reporter; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D046911:Macromolecular Substances; D051379:Mice; D009154:Mutation; D051419:Paxillin; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D020798:Two-Hybrid System Techniques
C117891:ASAP1 protein, human; D048868:Adaptor Proteins, Signal Transducing; D002135:Calcium-Binding Proteins; D002352:Carrier Proteins; D003598:Cytoskeletal Proteins; D005656:Fungal Proteins; D020690:GTPase-Activating Proteins; D047908:Intracellular Signaling Peptides and Proteins; D046911:Macromolecular Substances; C496061:PXN protein, human; D051419:Paxillin; D010750:Phosphoproteins; C496062:Pxn protein, mouse; C489722:REPS2 protein, human; C490620:Ralbp1 protein, mouse; D011993:Recombinant Fusion Proteins