Yeast phosphatidylinositol transfer protein Pdr17 does not require high affinity phosphatidylinositol binding for its cellular function

Publication date: Available online 11 July 2019Source: Biochimica et Biophysica Acta (BBA) - Molecular and Cell Biology of LipidsAuthor(s): Zuzana Pevalová, Vladimír Pevala, Nicholas J. Blunsom, Dana Tahotná, Veronika Kotrasová, Roman Holič, Lucia Pokorná, Jacob A. Bauer, Eva Kutejová, Shamshad Cockcroft, Peter GriačAbstractYeast phosphatidylinositol transfer protein (PITP) Pdr17 is an essential component of the complex required for decarboxylation of phosphatidylserine (PS) to phosphatidylethanolamine (PE) at a non-mitochondrial location. According to current understanding, this process involves the transfer of PS from the endoplasmic reticulum to the Golgi/endosomes. We generated a Pdr17E237A, K269A mutant protein to better understand the mechanism by which Pdr17p participates in the processes connected to the decarboxylation of PS to PE. We show that the Pdr17E237A, K269A mutant protein is not capable of binding phosphatidylinositol (PI) using permeabilized human cells, but still retains the ability to transfer PI between two membrane compartments in vitro. We provide data together with molecular models showing that the mutations E237A and K269A changed only the lipid binding cavity of Pdr17p and not its surface properties. In contrast to Pdr16p, a close homologue, the ability of Pdr17p to bind PI is not required for its major cellular function in the inter-membrane transfer of PS. We hypothesize that these two closely related yeast PITPs, Pdr16p and Pdr17p, have e...
Source: Biochimica et Biophysica Acta (BBA) Molecular and Cell Biology of Lipids - Category: Lipidology Source Type: research