HIGH RESOLUTION CRYSTAL STRUCTURE OF THE HUMAN PDK1 CATALYTIC DOMAIN
[PDPK1_HUMAN] Serine/threonine kinase which acts as a master kinase, phosphorylating and activating a subgroup of the AGC family of protein kinases. Its targets include: protein kinase B (PKB/AKT1, PKB/AKT2, PKB/AKT3), p70 ribosomal protein S6 kinase (RPS6KB1), p90 ribosomal protein S6 kinase (RPS6KA1, RPS6KA2 and RPS6KA3), cyclic AMP-dependent protein kinase (PRKACA), protein kinase C (PRKCD and PRKCZ), serum and glucocorticoid-inducible kinase (SGK1, SGK2 and SGK3), p21-activated kinase-1 (PAK1), protein kinase PKN (PKN1 and PKN2). Plays a central role in the transduction of signals from insulin by providing the activating phosphorylation to PKB/AKT1, thus propagating the signal to downstream targets controlling cell proliferation and survival, as well as glucose and amino acid uptake and storage. Negatively regulates the TGF-beta-induced signaling by: modulating the association of SMAD3 and SMAD7 with TGF-beta receptor, phosphorylating SMAD2, SMAD3, SMAD4 and SMAD7, preventing the nuclear translocation of SMAD3 and SMAD4 and the translocation of SMAD7 from the nucleus to the cytoplasm in response to TGF-beta. Activates PPARG transcriptional activity and promotes adipocyte differentiation. Activates the NF-kappa-B pathway via phosphorylation of IKKB. The tyrosine phosphorylated form is crucial for the regulation of focal adhesions by angiotensin II. Controls proliferation, survival, and growth of developing pancreatic cells. Participates in the regulation of Ca(2+) entry and Ca(2+)-activated K(+) channels of mast cells. Essential for the motility of vascular endothelial cells (ECs) and is involved in the regulation of their chemotaxis. Plays a critical role in cardiac homeostasis by serving as a dual effector for cell survival and beta-adrenergic response. Plays an important role during thymocyte development by regulating the expression of key nutrient receptors on the surface of pre-T cells and mediating Notch-induced cell growth and proliferative responses. Provides negative feedback inhibition to toll-like receptor-mediated NF-kappa-B activation in macrophages. Isoform 3 is catalytically inactive.              
Publication Abstract from PubMed
3-phosphoinositide dependent protein kinase-1 (PDK1) plays a key role in regulating signalling pathways by activating AGC kinases such as PKB/Akt and S6K. Here we describe the 2.0 A crystal structure of the PDK1 kinase domain in complex with ATP. The structure defines the hydrophobic pocket termed the "PIF-pocket", which plays a key role in mediating the interaction and phosphorylation of certain substrates such as S6K1. Phosphorylation of S6K1 at its C-terminal PIF-pocket-interacting motif promotes the binding of S6K1 with PDK1. In the PDK1 structure, this pocket is occupied by a crystallographic contact with another molecule of PDK1. Interestingly, close to the PIF-pocket in PDK1, there is an ordered sulfate ion, interacting tightly with four surrounding side chains. The roles of these residues were investigated through a combination of site-directed mutagenesis and kinetic studies, the results of which confirm that this region of PDK1 represents a phosphate-dependent docking site. We discuss the possibility that an analogous phosphate-binding regulatory motif may participate in the activation of other AGC kinases. Furthermore, the structure of PDK1 provides a scaffold for the design of specific PDK1 inhibitors.
High resolution crystal structure of the human PDK1 catalytic domain defines the regulatory phosphopeptide docking site.,Biondi RM, Komander D, Thomas CC, Lizcano JM, Deak M, Alessi DR, van Aalten DM EMBO J. 2002 Aug 15;21(16):4219-28. PMID:12169624
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.