High impact information on Pctp

• Phosphatidylcholine transfer protein (Pc-tp) is a highly specific carrier of phosphatidylcholine (PC) without known function [1].
• Absence of Pc-tp in bone marrow-derived mast cells does not affect their lipid composition or PC synthesis and degradation [1].
• In adult mice, Pc-tp levels are high only in epididymis, testis, kidney, and bone marrow-derived mast cells [1].
• We discuss how PC might reach the canalicular membrane of the hepatocyte for secretion into the bile, if not by Pc-tp [1].
• Homozygous disruption of Pctp modulates atherosclerosis in apolipoprotein E-deficient mice [2].

Biological context of Pctp

• In the absence of upregulation of hepatic ATP-binding cassette protein A1, reduced HDL uptake from plasma into livers of Pctp(-/-) mice contributed to higher plasma lipid concentrations [3].
• Phosphatidylcholine transfer protein (PC-TP) is a steroidogenic acute regulatory-related transfer domain protein that is enriched in liver cytosol and binds phosphatidylcholines with high specificity [3].
• Properties of these transfer proteins have been discussed with a special emphasis on the lipid binding site of bovine liver PC-TP [4].
• Radiation hybrid mapping localized the human gene, PCTP, to chromosome 17q21-22 and PCR-based single strand conformation polymorphism analysis of an interspecific backcross assigned mouse Pctp to the region of syntenic conservation on chromosome 11 [5].
• Phosphatidylcholine transfer protein (PC-TP) is a cytosolic phospholipid binding protein and a member of the steroidogenic acute regulatory-related transfer domain superfamily [2].

Anatomical context of Pctp

• In cholesteryl ester-loaded macrophages from Pctp(-/-) mice, the apolipoprotein AI-mediated efflux of phospholipids and cholesterol was decreased [6].
• Molecular cloning and characterization of phosphatidylcholine transfer protein-like protein gene expressed in murine haploid germ cells [7].

Associations of Pctp with chemical compounds

• In response to the lithogenic diet, a greater reduction in cholesterol 7alpha-hydroxylase activity in Pctp-/- mice could be attributed to increased size and hydrophobicity of the bile salt pool [8].
• Mice without phosphatidylcholine transfer protein have no defects in the secretion of phosphatidylcholine into bile or into lung airspaces [1].
• PC-TP containing a PC species carrying an sn-1 palmitoyl chain was less stable than PC-TP containing a PC species carrying an sn-1 stearoyl chain given that these complexes were dissociated for 50% at a cv of roughly 30 and 45 V, respectively [9].
• The various techniques which have been applied to establish the phospholipid localization include the following: phospholipase A2, phospholipase C, and sphingomyelinase C treatment, fluorescamine labeling of phosphatidylethanolamine, and a phosphatidylcholine transfer protein mediated exchange procedure [10].

Regulatory relationships of Pctp

• In tissue culture systems, PC-TP promotes ATP-binding cassette protein A1-mediated efflux of cholesterol and phosphatidylcholine molecules as nascent pre-beta-high-density lipoprotein (HDL) particles [3].
• In chow-fed mice, neither plasma cholesterol concentrations nor the concentrations and compositions of plasma phospholipids were influenced by PC-TP expression [3].

Other interactions of Pctp

• The lack of Acat upregulation suggests that, in the setting of the dietary challenge, the capacity for esterification to defend against hepatic accumulation of unesterified cholesterol was exceeded in the absence of PC-TP expression [8].
• In Pctp(-/-) mice fed the high-fat/high-cholesterol diet, HDL particle sizes were normalized, whereas plasma cholesterol and phospholipid concentrations were increased compared with wild-type mice [3].
• Hepatic phospholipid concentrations were also decreased in the absence of PC-TP and consequently, unesterified cholesterol-to-phospholipid ratios in liver remained unchanged [8].
• Phosphatidylcholine transfer protein (PC-TP) is a member of the steroidogenic acute regulatory transfer protein-related domain superfamily and is enriched in liver [8].
• The gene encoding phosphatidylcholine transfer protein (PC-TP) is sited within the support interval for Nidd3, a recessive NZO-derived locus on Chromosome 11 identified by prior segregation analysis between NZO/HlLt and NON/Lt [11].

Analytical, diagnostic and therapeutic context of Pctp

• Sequence analysis revealed that the NZO-derived PC-TP contained a non-synonymous point mutation that resulted in an Arg120His substitution, which was shared by the related NZB/BlNJ and NZW/LacJ mouse strains [11].

References