MOLECULAR-CLONING AND FUNCTIONAL EXPRESSION OF CDNA-ENCODING THE PIG PLASMA PHOSPHOLIPID TRANSFER PROTEIN

Citation
Pj. Pussinen et al., MOLECULAR-CLONING AND FUNCTIONAL EXPRESSION OF CDNA-ENCODING THE PIG PLASMA PHOSPHOLIPID TRANSFER PROTEIN, Journal of lipid research, 38(7), 1997, pp. 1473-1481
Citations number
27
Categorie Soggetti
Biology
Journal title
ISSN journal
00222275
Volume
38
Issue
7
Year of publication
1997
Pages
1473 - 1481
Database
ISI
SICI code
0022-2275(1997)38:7<1473:MAFEOC>2.0.ZU;2-R
Abstract
Humans and the pig show marked similarities in lipoprotein metabolism; therefore, the pig has been used as a model in numerous nutritional s tudies. Pig plasma displays no activity of cholesteryl ester transfer protein (CETP), which is known to be responsible for half of the phosp holipid mass transfer in human plasma, the other half being accounted for by the plasma phospholipid transfer protein (PLTP). This makes the pig an ideal subject for the study of PLTP structure and function. He re we report the molecular cloning of pig PLTP and the eukaryotic cell expression of its complementary DNA. Pig PLTP was found to share 93% amino acid sequence identity with human PLTP and 81% with mouse PLTP. Tissue expression of PLTP mRNA was examined by a method based on rever se transcription-polymerase chain reaction (RT-PCR) and solid-phase mi nisequencing in nine pig tissues. The highest PLTP mRNA levels were fo und in the pancreas, brain, lung, and liver. Medium from COS-1 cells e xpressing PLTP possessed phospholipid transfer activity, and the secre ted recombinant PLTP was detectable by Western blotting in the culture supernatant. A mutant protein with a substitution of Cys at position 22 by Arg was found to display impaired secretion into growth medium i ndicating a role for cysteines in the correct folding of PLTP. This st udy forms the basis for future work on the structure-function relation ships in pig PLTP.