Structural characterisation of the human phosphatidylinositol 4-kinase II alpha

Baumlova A.1, Chalupska D.1, Róźycki B.2, Jovic M.3, Wisniewski E.3, Klima M.1, Dubankova A.1, Kloer D.4, Nencka R.1, Balla T.3, Boura E.1

1Institute of Organic Chemistry and Biochemistry AS CR, Prague, Czech Republic.

2Institute of Physics Polish Academy of Sciences, Warsaw, Poland.

3Section on Molecular Signal Transduction, Program for Developmental Neuroscience, NICHD NIH, Bethesda, MD, USA

4Syngenta Jealott's Hill Internation Research Centre, Bracknell, UK.

boura@uochb.cas.cz

Phosphatidylinositol 4-kinase IIα (PI4K IIα) is one of the four mammalian lipid kinases that catalyse the conversion of phosphatidylinositol to phosphatidylinositol 4 phosphate, a major precursor of higher phosphoinositides and a key lipid molecule in a receptor-mediated signalling pathway [1]. Since PI4K IIa is a constitutively membrane bound protein, its enzymatic activity is modulated indirectly via changing the lipid composition and affecting the enzyme diffusion in a phospholipid bilayer [2]. The functional role of PI4K IIα in a cell physiology is still not fully understood. Here, we present the crystal structure of human PI4K IIα in complex with ATP [3]. The structure revealed a bi-lobal character (N- and C-lobes) of the catalytic domain with the ATP binding pocket positioned in between. Furthermore, a unique lateral hydrophobic pocket with a second ATP bound was found in the C-lobe of the catalytic domain. Molecular dynamic simulations and mutagenesis analysis revealed the membrane binding mode and a putative function of a lateral hydrophobic pocket. Altogether, these results provided the insight into a functional state of PI4IIα when bound to the membrane.

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3. A. Baumlova, D. Chalupska, B. Rozycki, M. Jovic, E. Wisniewski, M. Klima, A. Dubankova, D. Kloer, R. Nencka, T. Balla, E. Boura, EMBO Rep., 15, (2014)