PT  - JOURNAL ARTICLE
AU  - Joshua G. Pemberton
AU  - Yeun Ju Kim
AU  - Nivedita Sengupta
AU  - Andrea Eisenreichova
AU  - Daniel J. Toth
AU  - Evzen Boura
AU  - Tamas Balla
TI  - Defining the Subcellular Distribution and Metabolic Channeling of Phosphatidylinositol
AID  - 10.1101/677229
DP  - 2019 Jan 01
TA  - bioRxiv
PG  - 677229
4099  - http://biorxiv.org/content/early/2019/06/20/677229.short
4100  - http://biorxiv.org/content/early/2019/06/20/677229.full
AB  - Phosphatidylinositol (PtdIns) is an essential structural component of eukaryotic membranes that also serves as the common precursor for polyphosphoinositide (PPIn) lipids. Despite the recognized importance of PPIn species for signal transduction and membrane homeostasis, there is still a limited understanding of how the dynamic regulation of PtdIns synthesis and transport contributes to the turnover of PPIn pools. To address these shortcomings, we capitalized on the substrate selectivity of a bacterial enzyme, PtdIns-specific PLC, to establish a molecular toolbox for investigations of PtdIns distribution and availability within intact cells. In addition to its presence within the ER, our results reveal low steady-state levels of PtdIns within the plasma membrane (PM) and endosomes as well as a relative enrichment of PtdIns within the cytosolic leaflets of the Golgi complex, peroxisomes, and outer mitochondrial membranes. Kinetic studies also demonstrate the requirement for sustained PtdIns supply from the ER for the maintenance of monophosphorylated PPIn species within the PM, Golgi complex, and endosomal compartments.Summary Pemberton et al. characterize a molecular toolbox for the visualization and manipulation of phosphatidylinositol (PtdIns) within intact cells. Results using these approaches define the steady-state distribution of PtdIns across subcellular membrane compartments as well as provide new insights into the relationship between PtdIns availability and polyphosphoinositide turnover.