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Acyl chain-based molecular selectivity for HL60 cellular phosphatidylinositol and of phosphatidylcholine by phosphatidylinositol transfer protein ?

Acyl chain-based molecular selectivity for HL60 cellular phosphatidylinositol and of phosphatidylcholine by phosphatidylinositol transfer protein ?
Acyl chain-based molecular selectivity for HL60 cellular phosphatidylinositol and of phosphatidylcholine by phosphatidylinositol transfer protein ?
Mammalian phosphatidylinositol transfer protein ? (PITP) is an intracellular lipid transporter with a binding site that can accommodate a single molecule of phosphatidylinositol (PI) or phosphatidylcholine (PC). Phospholipids are a heterogeneous population of molecular species that can be distinguished by their characteristic headgroups as well as their acyl chains at the sn-1 and sn-2 position. In this study, we have defined the acyl chain preference for PITP? when presented with a total population of cellular lipids. Recombinant PITP? loaded with bacterial lipid, phosphatidylglycerol (PG), was incubated with permeabilised HL60 cells, followed by recovery of PITP? by affinity chromatography. Lipids extracted from the PITP? were analysed by tandem electrospray ionisation mass spectrometry (ESI-MS) and showed total exchange of acquired bacterial lipids for HL60 cellular PI and PC. Detailed comparison of the molecular species composition of bound phospholipids with those in whole cells permitted the assessment of selectivity of acyl chain binding. For both phospholipid classes, progressive fractional enrichments in bound species possessing shorter acyl chains were apparent with a preference order: 16:1>16:0>18:1>18:0>20:4. A recapitulation of this specificity order was also seen from a dramatically altered range of molecular species present in HL60 cells enriched with arachidonate over many weeks of culture. We speculate that short-chain, saturate-binding preferences under both conditions may reflect properties in vivo. This is consistent with target cell membranes actively remodelling newly delivered phospholipids after transport rather than relying on the transport of the specific molecular species conventionally found in mammalian membranes.
phosphatidylinositol transfer protein, acyl chains of phospholipids, mass spectrometry, phosphatidylcholine, phosphatidylinositol, HL60 cell
1388-1981
50-60
Hunt, Alan N.
95a3e223-da96-40e7-b47d-27dce014e305
Skippen, Alison J.
8bb240a3-1085-4fb3-a539-7609f636ea85
Koster, Grielof
e404c38a-6f48-430a-adf0-5208228cb9e7
Postle, Anthony D.
0fa17988-b4a0-4cdc-819a-9ae15c5dad66
Cockcroft, Shamshad
e11ebfa8-cd2e-4339-ba8c-dd97f724fd50
Hunt, Alan N.
95a3e223-da96-40e7-b47d-27dce014e305
Skippen, Alison J.
8bb240a3-1085-4fb3-a539-7609f636ea85
Koster, Grielof
e404c38a-6f48-430a-adf0-5208228cb9e7
Postle, Anthony D.
0fa17988-b4a0-4cdc-819a-9ae15c5dad66
Cockcroft, Shamshad
e11ebfa8-cd2e-4339-ba8c-dd97f724fd50

Hunt, Alan N., Skippen, Alison J., Koster, Grielof, Postle, Anthony D. and Cockcroft, Shamshad (2004) Acyl chain-based molecular selectivity for HL60 cellular phosphatidylinositol and of phosphatidylcholine by phosphatidylinositol transfer protein ? Biochimica et Biophysica Acta (BBA) - Molecular and Cell Biology of Lipids, 1686 (1-2), 50-60. (doi:10.1016/j.bbalip.2004.08.003).

Record type: Article

Abstract

Mammalian phosphatidylinositol transfer protein ? (PITP) is an intracellular lipid transporter with a binding site that can accommodate a single molecule of phosphatidylinositol (PI) or phosphatidylcholine (PC). Phospholipids are a heterogeneous population of molecular species that can be distinguished by their characteristic headgroups as well as their acyl chains at the sn-1 and sn-2 position. In this study, we have defined the acyl chain preference for PITP? when presented with a total population of cellular lipids. Recombinant PITP? loaded with bacterial lipid, phosphatidylglycerol (PG), was incubated with permeabilised HL60 cells, followed by recovery of PITP? by affinity chromatography. Lipids extracted from the PITP? were analysed by tandem electrospray ionisation mass spectrometry (ESI-MS) and showed total exchange of acquired bacterial lipids for HL60 cellular PI and PC. Detailed comparison of the molecular species composition of bound phospholipids with those in whole cells permitted the assessment of selectivity of acyl chain binding. For both phospholipid classes, progressive fractional enrichments in bound species possessing shorter acyl chains were apparent with a preference order: 16:1>16:0>18:1>18:0>20:4. A recapitulation of this specificity order was also seen from a dramatically altered range of molecular species present in HL60 cells enriched with arachidonate over many weeks of culture. We speculate that short-chain, saturate-binding preferences under both conditions may reflect properties in vivo. This is consistent with target cell membranes actively remodelling newly delivered phospholipids after transport rather than relying on the transport of the specific molecular species conventionally found in mammalian membranes.

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Published date: 2004
Keywords: phosphatidylinositol transfer protein, acyl chains of phospholipids, mass spectrometry, phosphatidylcholine, phosphatidylinositol, HL60 cell

Identifiers

Local EPrints ID: 27166
URI: http://eprints.soton.ac.uk/id/eprint/27166
ISSN: 1388-1981
PURE UUID: 5061ce5b-b79d-4e25-83bd-c87e399e2606
ORCID for Alan N. Hunt: ORCID iD orcid.org/0000-0001-5938-2152
ORCID for Anthony D. Postle: ORCID iD orcid.org/0000-0001-7361-0756

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Date deposited: 26 Apr 2006
Last modified: 16 Mar 2024 02:48

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Contributors

Author: Alan N. Hunt ORCID iD
Author: Alison J. Skippen
Author: Grielof Koster
Author: Shamshad Cockcroft

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