Mttp
Developmental stage
Expression in the yolk sac tissues followed by expression in the primordial liver cell nests as early as day 9 post-coitum (9.5 dpc). Intestinal expression is detected around 12.5 dpc and attains full adult expression patterns by 14.5 dpc.
Function
Catalyzes the transport of triglyceride, cholesteryl ester, and phospholipid between phospholipid surfaces (PubMed:15897609, PubMed:16478722, PubMed:18502767, PubMed:33168624). Required for the assembly and secretion of plasma lipoproteins that contain apolipoprotein B (PubMed:10713055, PubMed:17635917, PubMed:18502767, PubMed:33168624, PubMed:9502759). May be involved in regulating cholesteryl ester biosynthesis in cells that produce lipoproteins (PubMed:18502767).
Isoform 2
Critical for the development of natural killer T (NKT) cells (PubMed:17312007). Required for the assembly and secretion of plasma lipoproteins that contain apolipoprotein B (PubMed:17635917).
Post-translational modifications
Isoform 2
Cleaved by signal peptidase between residues Gln-33 and Asn-34.
Tissue Specificity
Isoform 1
Mainly expressed in the intestine and the liver, and at lower levels in white and brown fat cells (PubMed:17635917, PubMed:8660984). Expressed in heart (PubMed:9502759).
Isoform 2
Ubiquitous, and is the major isoform in hematopoietic cells and adipocytes.
Cellular localization
- Endoplasmic reticulum
- Isoform 1
- Endoplasmic reticulum
- Golgi apparatus
- Colocalizes with P4HB/PDI in the endoplasmic reticulum (By similarity).
- Isoform 2
- Endoplasmic reticulum
- Golgi apparatus
Alternative names
Mtp, Mttp, Microsomal triglyceride transfer protein large subunit