Structural basis for UCN-01 (7-hydroxystaurosporine) specificity and PDK1 (3-phosphoinositide-dependent protein kinase-1) inhibition.
PDK1 (3-phosphoinositide-dependent protein kinase-1) is a member of the AGC (cAMP-dependent, cGMP-dependent, protein kinase C) family of protein kinases, and has a key role in insulin and growth-factor signalling through phosphorylation and subsequent activation of a number of other AGC kinase family members, such as protein kinase B. The staurosporine derivative UCN-01 (7-hydroxystaurosporine) has been reported to be a potent inhibitor for PDK1, and is currently undergoing clinical trials for the treatment of cancer. Here, we report the crystal structures of staurosporine and UCN-01 in complex with the kinase domain of PDK1. We show that, although staurosporine and UCN-01 interact with the PDK1 active site in an overall similar manner, the UCN-01 7-hydroxy group, which is not present in staurosporine, generates direct and water-mediated hydrogen bonds with active-site residues. Inhibition data from UCN-01 tested against a panel of 29 different kinases show a different pattern of inhibition compared with staurosporine. We discuss how these differences in inhibition could be attributed to specific interactions with the additional 7-hydroxy group, as well as the size of the 7-hydroxy-group-binding pocket. This information could lead to opportunities for structure-based optimization of PDK1 inhibitors.
Komander
David
D
Division of Biological Chemistry and Molecular Microbiology, School of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland, UK.
Kular
Gursant S
GS
Bain
Jennifer
J
Elliott
Matthew
M
Alessi
Dario R
DR
Van Aalten
Daan M F
DM
D064413:3-Phosphoinositide-Dependent Protein Kinases; D000818:Animals; D001665:Binding Sites; D020134:Catalytic Domain; D002460:Cell Line; D018360:Crystallography, X-Ray; D004791:Enzyme Inhibitors / Q000737:chemistry / Q000494:pharmacology; D006801:Humans; D008958:Models, Molecular; D008968:Molecular Conformation; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000235:genetics; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism; D018411:Spodoptera; D019311:Staurosporine / Q000031:analogs & derivatives* / Q000737:chemistry* / Q000494:pharmacology; D013329:Structure-Activity Relationship
D004791:Enzyme Inhibitors; D011994:Recombinant Proteins; C054852:7-hydroxystaurosporine; D064413:3-Phosphoinositide-Dependent Protein Kinases; C578562:PDPK1 protein, human; D017346:Protein Serine-Threonine Kinases; D019311:Staurosporine