The function of ENSG00000138823 (MTTP, microsomal triglyceride transfer protein) is as follows. Catalyzes the transport of triglyceride, cholesteryl ester, and phospholipid between phospholipid surfaces (PubMed:15897609, PubMed:16478722, PubMed:22236406, PubMed:23475612, PubMed:25108285, PubMed:26224785, PubMed:8876250, PubMed:8939939). Required for the assembly and secretion of plasma lipoproteins that contain apolipoprotein B (PubMed:16478722, PubMed:23475612, PubMed:26224785, PubMed:8876250, PubMed:8939939). May be involved in regulating cholesteryl ester biosynthesis in cells that produce lipoproteins (By similarity). {ECO:0000250|UniProtKB:O08601, ECO:0000269|PubMed:15897609, ECO:0000269|PubMed:16478722, ECO:0000269|PubMed:22236406, ECO:0000269|PubMed:23475612, ECO:0000269|PubMed:25108285, ECO:0000269|PubMed:26224785, ECO:0000269|PubMed:8876250, ECO:0000269|PubMed:8939939}.