Author/Editor		Bradbury, Paul; Griffith Mann, C.; Köchl, Silvano; Anderson, Timothy A.; Chester, Ann; Hancock, John M.
Title		A common binding site on the microsomal triglyceride transfer protein for apolipoprotein B and protein disulfide isomerase
Type		članek
Vol. and No.		Letnik 274, št. 5
Publication year		1999
Volume		str. 3159 ‐3164
ISSN		0021-9258 - The Journal of biological chemistry
Language		eng
Abstract		The assembly of triglyceride-rich lipoproteins requires the formation in the endoplasmic reticulum of a complex between apolipoprotein B (apoB), a microsomal triglyceride transfer protein (MTP), and protein disulfide isomerase (PDI). In the MTP complex, the amino-terminal region of MTP (residues 22-303) interacts with the amino-terminal region of apoB (residues 1-264). Here, we report the identification and characterization of a site on apoB between residues 512 and 721, which interacts with residues 517-603 of MTP. PDI binds in close proximity to this apoB binding site on MTP. The proximity of these binding sites on MTP for PDI and amino acids 512-721 of apoB was evident from studies carried out in a yeast two-hybrid system and by co-immunoprecipitation. The expression of PDI with MTP and apoB16 (residues 1-721) in the baculovirus expression system reduced the amount of MTP co-immunoprecipitated with apoB by 73%. The interaction of residues 512-721 of apoB with MTP facilitates lipoprotein production. Mutations of apoB that markedly reduced this interaction also reduced the level of apoB-containing lipoprotein secretion.
Keywords		lipoproteins microsomal triglyceride transfer protein disulfide isomerase lipoproteini prenos mikrosomskih trigliceridov protein disulfid izomeraza