Phosphoinositide-dependent kinase-1 orthologues from five eukaryotes are activated by the hydrophobic motif in AGC kinases.
Phosphoinositide-dependent kinase-1 (PDK1) mediates activation of many AGC kinases by docking onto a phosphorylated hydrophobic motif located C-terminal of the catalytic domain in the AGC kinase. The interaction shifts PDK1 into a conformation with increased catalytic activity and leads to autophosphorylation of PDK1. We demonstrate here that addition of a hydrophobic motif peptide increases the catalytic activity of PDK1 orthologues from Homo sapiens, Aplysia californica, Arabidopsis thaliana, Schizosaccharomyces pombe (ksg1), and Saccharomyces cerevisiae (Pkh1 and Pkh2) 2- to 12-fold. Furthermore, the hydrophobic motif peptide increases autophosphorylation of PDK1 from Homo sapiens, S. pombe, and S. cerevisiae (Phk2). Our results suggest that PDK1 interaction and activation by the hydrophobic motif of AGC kinases is a central mechanism in PDK1 function, which is conserved during eukaryotic evolution.
Silber
Joachim
J
Department of Clinical Biochemistry, Glostrup Hospital, DK-2600 Glostrup, Denmark. js@mb.au.dk
Antal
Torben L
TL
Gammeltoft
Steen
S
Rasmussen
Thomas E
TE
D064413:3-Phosphoinositide-Dependent Protein Kinases; D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D001048:Aplysia / Q000201:enzymology / Q000235:genetics; D017360:Arabidopsis / Q000201:enzymology / Q000235:genetics; D020134:Catalytic Domain; D004789:Enzyme Activation; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D066298:In Vitro Techniques; D008969:Molecular Sequence Data; D010802:Phylogeny; D011487:Protein Conformation; D011494:Protein Kinases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000235:genetics; D012568:Schizosaccharomyces / Q000201:enzymology / Q000235:genetics
D011494:Protein Kinases; D064413:3-Phosphoinositide-Dependent Protein Kinases; C578562:PDPK1 protein, human; D017346:Protein Serine-Threonine Kinases