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MTTP
Available structures
PDB	Ortholog search: PDBe RCSB
List of PDB id codes
	6I7S, 8EOJ
Identifiers
Aliases	MTTP, ABL, MTP, Microsomal triglyceride transfer protein
External IDs	OMIM: 157147; MGI: 106926; HomoloGene: 212; GeneCards: MTTP; OMA:MTTP - orthologs
Gene location (Human)
Chr.	Chromosome 4 (human)
End	99,623,997 bp
Gene location (Mouse)
Chr.	Chromosome 3 (mouse)
End	137,850,729 bp
RNA expression pattern
	Top expressed in
	jejunal mucosa; ; mucosa of ileum; ; liver; ; duodenum; ; right lobe of liver; ; testicle; ; ventricular zone; ; kidney tubule; ; gonad; ; human kidney;
	Top expressed in
	jejunum; ; duodenum; ; migratory enteric neural crest cell; ; left lobe of liver; ; ileum; ; yolk sac; ; spermatocyte; ; intestinal epithelium; ; crypt of lieberkuhn of small intestine; ; spermatid;
	More reference expression data
	More reference expression data
Gene ontology
Molecular function	protein heterodimerization activity; protein binding; phospholipid transporter activity; lipid binding; lipid transporter activity;
Cellular component	receptor complex; endoplasmic reticulum lumen; endoplasmic reticulum; Golgi apparatus; basolateral plasma membrane;
Biological process	phospholipid transport; lipid transport; plasma lipoprotein particle assembly; lipid metabolism; protein secretion; triglyceride transport; chylomicron assembly; very-low-density lipoprotein particle assembly; lipoprotein metabolic process; cholesterol homeostasis;
	Sources:Amigo / QuickGO
Orthologs
	4547
	17777
	ENSG00000138823
	ENSMUSG00000028158
	P55157
	O08601
	NM_001300785; NM_000253; NM_001386140
	NM_001163457; NM_008642; NM_001355051; NM_001355052
	NP_000244; NP_001287714
	NP_001156929; NP_032668; NP_001341980; NP_001341981
	Wikidata
View/Edit Human	View/Edit Mouse

Microsomal triglyceride transfer protein large subunit is a protein that in humans is encoded by the MTTP, also known as MTP, gene.^[5]^[6]

MTTP encodes the large subunit of the heterodimeric microsomal triglyceride transfer protein (MTP). Protein disulfide isomerase (PDI) completes the heterodimeric MTP, which has been shown to play a central role in lipoprotein assembly. Mutations in MTTP can cause abetalipoproteinemia.^[6]

Apolipoprotein B48 on chylomicra and Apolipoprotein B100 on LDL, IDL, and VLDL are important for MTP binding.^{[citation needed]}

MTP adds triglycerides to nascent chylomicrons in the intestine, and to VLDL in the liver.^[7]

Structure

The large subunit of MTP, also known as the alpha subunit, contains an N-terminal half beta barrel, an alpha helix and a C-terminal lipid binding site that lies between two beta pleated sheets. It is a member of the large lipid transfer protein family, like apolipoprotein B (apo B), with which it interacts, but unlike apo B, it is not secreted. The heterodimer is instead retained in the endoplasmic reticulum due to the presence of a C-terminal KDEL motif on the PDI beta subunit.^[8]

Interactive pathway map

Click on genes, proteins and metabolites below to link to respective articles. ^{[§ 1]}

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|alt=Statin pathway edit]]

Statin pathway edit

^ The interactive pathway map can be edited at WikiPathways: "Statin_Pathway_WP430".

Pharmacology

Drugs that inhibit MTTP prevent the assembly of apo B-containing lipoproteins thus inhibiting the synthesis of chylomicrons and VLDL and leading to decrease in plasma levels of LDL-C.

Lomitapide (Juxtapid) was approved by the US FDA for adjunctive treatment of homozygous familial hypercholesterolemia.
Dirlotapide (Slentrol) and mitratapide (Yarvitan) are veterinary drugs for the management of obesity in dogs.

References

^ ^a ^b ^c GRCh38: Ensembl release 89: ENSG00000138823 – Ensembl, May 2017
^ ^a ^b ^c GRCm38: Ensembl release 89: ENSMUSG00000028158 – Ensembl, May 2017
^ "Human PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
^ "Mouse PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
^ Shoulders CC, Brett DJ, Bayliss JD, Narcisi TM, Jarmuz A, Grantham TT, Leoni PR, Bhattacharya S, Pease RJ, Cullen PM, et al. (Mar 1994). "Abetalipoproteinemia is caused by defects of the gene encoding the 97 kDa subunit of a microsomal triglyceride transfer protein". Hum Mol Genet. 2 (12): 2109–16. doi:10.1093/hmg/2.12.2109. PMID 8111381.
^ ^a ^b "Entrez Gene: MTTP microsomal triglyceride transfer protein".
^ Katzung BG (2018). Basic & Clinical Pharmacology (14th ed.). McGraw-Hill Education. p. 638. ISBN 978-1-259-64115-2.
^ Biterova EI, Isupov MN, Keegan RM, Lebedev AA, Sohail AA, Liaquat I, Alanen HI, Ruddock LW (2019). "The crystal structure of human microsomal triglyceride transfer protein". Proceedings of the National Academy of Sciences of the United States of America. 116 (35): 17251–17260. Bibcode:2019PNAS..11617251B. doi:10.1073/pnas.1903029116. PMC 6717300. PMID 31395737.