| A hallmark of signal transduction pathways is the reversible phosphorylation of serine and threonine residues within specific sequences, or motifs, in target proteins. Specific signaling motifs include not only sequences that are recognized by protein kinases (1), but also those that are recognized by phosphorylation-dependent binding proteins such as 14-3-3 (2). These modular phosphoprotein interacting domains are critical elements in modulating, directing and amplifying intracellular communications.Many critical protein kinases can be regulated by phosphorylation at a specific serine or threonine in a hydrophobic motif (3). For example, Akt, a kinase that regulates cell survival, is activated by phosphorylation at Ser473, a site preceded by Phe at -4 and -1 and followed by Tyr at +1 (4). RSK2, p70 S6 kinase and certain PKC isoforms also contain a similar consensus phosphorylation motif. Phosphorylation of these motifs is required for binding to 3-phosphoinositide-dependent kinase 1 (PDK1) (5-7). Phospho-(Ser/Thr) PDK1 Docking Motif (18A2) Monoclonal Antibody is a powerful tool for the characterization of phosphorylated PDK1 docking motifs and the identification of new proteins with PDK1 docking motifs. |
