Interaction of POB1, a downstream molecule of small G protein Ral, with PAG2, a paxillin-binding protein, is involved in cell migration

Takafumi Oshiro; Shinya Koyama; Shinichiro Sugiyama; Akiko Kondo; Yasuhito Onodera; Toshimasa Asahara; Hisataka Sabe; Akira Kikuchi

doi:10.1074/jbc.M203453200

Interaction of POB1, a downstream molecule of small G protein Ral, with PAG2, a paxillin-binding protein, is involved in cell migration

J Biol Chem. 2002 Oct 11;277(41):38618-26. doi: 10.1074/jbc.M203453200. Epub 2002 Jul 30.

Authors

Takafumi Oshiro¹, Shinya Koyama, Shinichiro Sugiyama, Akiko Kondo, Yasuhito Onodera, Toshimasa Asahara, Hisataka Sabe, Akira Kikuchi

Affiliation

¹ Department of Biochemistry, Graduate School of Biomedical Sciences, Hiroshima University, 1-2-3, Kasumi, Minami-ku, Hiroshima 734-8551, Japan.

PMID: 12149250
DOI: 10.1074/jbc.M203453200

Abstract

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.

MeSH terms

Adaptor Proteins, Signal Transducing
Amino Acid Motifs
Animals
Calcium-Binding Proteins
Carrier Proteins / chemistry
Carrier Proteins / genetics
Carrier Proteins / metabolism*
Cell Line
Cell Movement / physiology*
Cytoskeletal Proteins / genetics
Cytoskeletal Proteins / metabolism
Focal Adhesions
Fungal Proteins / genetics
Fungal Proteins / metabolism*
GTPase-Activating Proteins / chemistry
GTPase-Activating Proteins / genetics
GTPase-Activating Proteins / metabolism*
Genes, Reporter
Humans
Intracellular Signaling Peptides and Proteins*
Macromolecular Substances
Mice
Mutation
Paxillin
Phosphoproteins / genetics
Phosphoproteins / metabolism*
Protein Binding
Recombinant Fusion Proteins / genetics
Recombinant Fusion Proteins / metabolism
Two-Hybrid System Techniques

Substances

ASAP1 protein, human
Adaptor Proteins, Signal Transducing
Calcium-Binding Proteins
Carrier Proteins
Cytoskeletal Proteins
Fungal Proteins
GTPase-Activating Proteins
Intracellular Signaling Peptides and Proteins
Macromolecular Substances
PXN protein, human
Paxillin
Phosphoproteins
Pxn protein, mouse
REPS2 protein, human
Ralbp1 protein, mouse
Recombinant Fusion Proteins