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.
Mesh Terms:
Adaptor Proteins, Signal Transducing, Amino Acid Motifs, Animals, Carrier Proteins, Cell Line, Cell Movement, Cytoskeletal Proteins, Focal Adhesions, Fungal Proteins, GTPase-Activating Proteins, Genes, Reporter, Humans, Intracellular Signaling Peptides and Proteins, Macromolecular Substances, Mice, Mutation, Paxillin, Phosphoproteins, Protein Binding, Recombinant Fusion Proteins, Two-Hybrid System Techniques
J. Biol. Chem.
Date: Oct. 11, 2002
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