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Multistep Compositional Remodeling of Supported Lipid Membranes by Interfacially Active Phosphatidylinositol Kinases ANALYTICAL CHEMISTRY Tabaei, S. R., Guo, F., Rutaganira, F. U., Vafaei, S., Choong, I., Shokat, K. M., Glenn, J. S., Cho, N. 2016; 88 (10): 5042-5045

Abstract

The multienzyme catalytic phosphorylation of phosphatidylinositol (PI) in a supported lipid membrane platform is demonstrated for the first time. One-step treatment with PI 4-kinase IIIß (PI4Kß) yielded PI 4-phosphate (PI4P), while a multistep enzymatic cascade of PI4Kß followed by PIP 5-kinase produced PI-4,5-bisphosphate (PI(4,5)P2 or PIP2). By employing quartz crystal microbalance with dissipation monitoring, we were able to track membrane association of kinase enzymes for the first time as well as detect PI4P and PI(4,5)P2 generation based on subsequent antibody binding to the supported lipid bilayers. Pharmacologic inhibition of PI4Kß by a small molecule inhibitor was also quantitatively assessed, yielding an EC50 value that agrees well with conventional biochemical readout. Taken together, the development of a PI-containing supported membrane platform coupled with surface-sensitive measurement techniques for kinase studies opens the door to exploring the rich biochemistry and pharmacological targeting of membrane-associated phosphoinositides.

View details for DOI 10.1021/acs.analchem.6b01293

View details for PubMedID 27118725