title: Ligand and membrane-binding behavior of the phosphatidylinositol transfer proteins PITPα and PITPβ.
abstract: Phosphatidylinositol transfer proteins (PITPs) are believed to be lipid transfer proteins because of their ability to transfer either phosphatidylinositol (PI) or phosphatidylcholine (PC) between membrane compartments, in vitro. However, the detailed mechanism of this transfer process is not fully established. To further understand the transfer mechanism of PITPs we examined the interaction of PITPs with membranes using dual polarization interferometry (DPI), which measures protein binding affinity on a flat immobilized lipid surface. In addition, a fluorescence resonance energy transfer (FRET)-based assay was also employed to monitor how quickly PITPs transfer their ligands to lipid vesicles. DPI analysis revealed that PITPβ had a higher affinity to membranes compared with PITPα. Furthermore, the FRET-based transfer assay revealed that PITPβ has a higher ligand transfer rate compared with PITPα. However, both PITPα and PITPβ demonstrated a preference for highly curved membrane surfaces during ligand transfer. In other words, ligand transfer rate was higher when the accepting vesicles were highly curved.
authors: a Department of Chemistry and Centre for Biotechnology, Brock University, St. Catharines, ON L2A 3S1, Canada.
authors: Matilda
authors: M
authors: Baptist
authors: a Department of Chemistry and Centre for Biotechnology, Brock University, St. Catharines, ON L2A 3S1, Canada.
authors: Candace
authors: C
authors: Panagabko
authors: b Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6JJ, UK.
authors: Shamshad
authors: S
authors: Cockcroft
authors: a Department of Chemistry and Centre for Biotechnology, Brock University, St. Catharines, ON L2A 3S1, Canada.
authors: Jeffrey
authors: J
authors: Atkinson
mesh_terms: D002462:Cell Membrane / Q000378:metabolism*; D031541:Fluorescence Resonance Energy Transfer; D006801:Humans; D008024:Ligands; D008055:Lipids / Q000737:chemistry*; D009154:Mutation / Q000235:genetics; D010716:Phosphatidylinositols / Q000737:chemistry / Q000378:metabolism*; D049294:Phospholipid Transfer Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D011487:Protein Conformation
chemical_list: D008024:Ligands; D008055:Lipids; C493463:PITPNA protein, human; C493470:PITPNB protein, human; D010716:Phosphatidylinositols; D049294:Phospholipid Transfer Proteins
keywords: dual polarization interferometry; fluorescence resonance energy transfer; interférométrie à double polarisation; liaison protéine–membrane; phosphatidylinositol transfer protein; protein–membrane binding; protéine de transfert du phosphatidylinositol; transfert d’énergie de fluorescence par résonance