Microsomal triglyceride transfer protein in plasma and cellular lipid metabolism.
OBJECTIVE
This review summarizes recent advances about the role of microsomal triglyceride transfer protein in plasma and tissue lipid homeostasis.


RESULTS
Microsomal triglyceride transfer protein emerged as a phospholipid transfer protein and acquired triacylglycerol transfer activity during evolution from invertebrates to vertebrates. These activities are proposed to participate in 'nucleation' and 'desorption' steps during the biosynthesis of primordial apoB-containing lipoproteins. Microsomal triglyceride transfer protein also transfers phospholipids to the glycolipid antigen presentation molecule CD1d. Under physiologic conditions, plasma apoB-containing lipoproteins and microsomal triglyceride transfer protein expression exhibit diurnal variations synchronized by food and light. Microsomal triglyceride transfer protein is regulated at the transcriptional level. HNF4alpha is critical for its transcription. Other transcription factors along with coactivators and corepressors modulate microsomal triglyceride transfer protein expression. Reductions in microsomal triglyceride transfer protein mRNA and activity are related to steatosis in HCV-3 infected patients. CCl4 induces steatosis by enhancing proteasomal degradation of microsomal triglyceride transfer protein and can be partially avoided by inhibiting this degradation. Chemical antagonists cause hepatosteatosis, but this was not seen in the absence of fatty acid binding protein.


CONCLUSIONS
Microsomal triglyceride transfer protein is a target to lower plasma lipids and to reduce inflammation in certain immune disorders. More knowledge is required, however, regarding its regulation and its role in the biosynthesis of apoB-containing lipoproteins and CD1d.
Hussain
M Mahmood
MM
Department of Anatomy and Cell Biology, SUNY Downstate Medical Center, Brooklyn, New York 11203, USA. mhussain@downstate.edu
Rava
Paul
P
Pan
Xiaoyue
X
Dai
Kezhi
K
Dougan
Stephanie K
SK
Iqbal
Jahangir
J
Lazare
Farrah
F
Khatun
Irani
I
D000818:Animals; D018949:Antigens, CD1 / Q000096:biosynthesis; D055610:Antigens, CD1d; D001055:Apolipoproteins B / Q000378:metabolism; D002352:Carrier Proteins / Q000097:blood* / Q000235:genetics / Q000502:physiology; D005234:Fatty Liver / Q000378:metabolism; D005786:Gene Expression Regulation; D006801:Humans; D050356:Lipid Metabolism; D051379:Mice; D014158:Transcription, Genetic
D018949:Antigens, CD1; D055610:Antigens, CD1d; D001055:Apolipoproteins B; C526877:CD1D protein, human; D002352:Carrier Proteins; C106092:microsomal triglyceride transfer protein