Disease relevance of MT1B

• In support of this notion, we found that the 5' flanking region of the hMT-IB gene was highly methylated in HeLa cells, a nonexpressing cell type, but it was not methylated in a hepatoma (expressing) cell line [1].
• The MT-2A isoform was the most abundant MT isoform in both normal and keloid keratinocytes while the MT-1B isoform was absent [2].
• Recombinant (E. coli ) synthesis of mammalian MT1 and MT4 domains as separate peptides in Zn(II) and Cd(II) enriched growth media has rendered metal complexes containing sulfide anions as additional ligands [3].
• OBJECTIVE: To detect the message for membrane type 1 (MT1) matrix metalloproteinase (MMP) in articular cartilage and chondrosarcoma cells, to study its expression in osteoarthritis (OA), and to determine whether interleukin-1beta (IL-1beta) influences its expression [4].
• Cultured fibroblasts from patients with Menkes' disease accumulate excess Cu which chromatographs both with high-molecular-weight protein(s) and with a Cu-MTP [5].

High impact information on MT1B

• MTP shares morphological, biochemical, and functional properties attributed to bacterial pili, especially with curli amyloid fibers [6].
• This phenotype was mimicked by the cytoplasmic truncation mutant MT1 Delta C with more robust pro-MMP-2 activation and cell surface expression than wild-type MT1-MMP in transfected cells [7].
• Internalization experiments revealed that MT1-MMP is internalized rapidly in clathrin-coated vesicles whereas MT1 Delta C remains on cell surface [7].
• Repair of UV damage in the hMT-IB gene, which shows cell-type specific expression, and in the hMT-IIB gene, which is a nontranscribed processed pseudogene, was about the same as in the rest of the genome, whereas repair of AFB1-induced damage was deficient in these two genes [8].
• Unlike the hMT-IIA and hMT-IA genes described previously, which are expressed in many different cell types, a high level of expression of the endogenous hMT-IB gene could be detected only in human hepatoma and renal carcinoma cell lines [1].

Chemical compound and disease context of MT1B

• Naringenin, the principal flavonoid in grapefruit, reduces plasma lipids in vivo and inhibits apoB secretion, cholesterol esterification, and MTP activity in HepG2 human hepatoma cells [9].
• The safety and efficacy of a full-length sucrose-formulated recombinant factor VIII product (rFVIII-FS; Kogenate FS; Kogenate Bayer) was evaluated in previously untreated (PUPs) and minimally treated (MTP) patients with severe haemophilia A (FVIII <2%) [10].
• The EORTC Soft Tissue and Bone Sarcoma Group conducted a phase II study with intravenous muramyl tripeptide phosphatidylethanolamine (MTP/PE) at a dose of 4 mg once weekly in 20 patients with metastatic soft tissue sarcomas [11].
• Patients with very long-chain acyl-CoA dehydrogenase (VLCAD) and long-chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD)/mitochondrial trifunctional protein (MTP) deficiency, disorders of the mitochondrial long-chain fatty acid oxidation, can present with hypoketotic hypoglycemia, rhabdomyolysis, and cardiomyopathy [12].
• Pre-operative patients with benign diseases (diverticulitis, adenoma = GID; and mastopathy = MTP) showed increased GLU levels, which were comparable to those of the tumour patients [13].

Biological context of MT1B

• Like other MT genes, hMT-IB has at least two copies of the metal-responsive element upstream from the transcription initiation site [1].
• This specificity is controlled by a cis-acting mechanism involving methylation, since incubation of nonexpressing cells with an inhibitor of DNA methylation led to activation of the hMT-IB gene [1].
• The levels of gene expression of MT-1A, 1E, 1F, 1G, 1H, and 1X increased, but the level of MT-1B did not increase after exposure to cadmium [14].
• Bmal-1, Per-2, and the melatonin 1 receptor (MT1) showed a robust oscillatory expression in SCN and adrenal gland, whereas a circadian rhythm of dehydroepiandrosterone sulphate was found in plasma [15].
• A metallothionein-like protein (MTP) is synthesized in normal diploid human skin fibroblasts cultured in Zn- or Cu-supplemented medium [5].

Anatomical context of MT1B

• To evaluate the role of MT2A expression, MT2A and MT1B were overexpressed in HeLa cells and treated with rotenone [16].
• The affinities and the functional activities of these ligands were compared with the human receptors (hMT1 or hMT2) expressed in CHO cells as well [17].
• The present studies were undertaken to examine whether or not the transfer of TG to nascent apoB in the endoplasmic reticulum involves the physical interaction between MTP and apoB [18].
• However, Menkes fibroblasts retain the ability to incorporate 65Zn into MTP in response to Zn supplementation of the medium [5].
• Synthesis of MTP is not detected in cells cultured without metal supplementation of complete tissue-culture medium [5].

Associations of MT1B with chemical compounds

• Expression of MT2A (MT isoform 2A), but not MT1A or MT1B RNA, was significantly inducible by rotenone (up to 7-fold), t-BHP (t-butyl hydroperoxide; 5-fold) and CdCl2 (50-fold), but not ZnCl2 [16].
• The Zn- and Cd-Clusters of Recombinant Mammalian MT1 and MT4 Metallothionein Domains Include Sulfide Ligands [3].
• The mRNA expression of melatonin receptor subtype MT1 and MT2 were detected by RT-PCR method [19].
• N-Acetyl-leucyl-leucyl-norleucinal, a cysteine protease inhibitor, which directly protects apoB from rapid intracellular degradation but does not affect TG synthesis, increased the interaction between MTP and apoB only slightly, although it did prolong it [18].
• Microsomal triglyceride (TG) transfer protein (MTP) is an endoplasmic reticulum lumenal protein consisting of a 97-kDa subunit and protein disulfide isomerase [18].

Other interactions of MT1B

• Except of MT3, already known as brain-specific, and MT1B which was not expressed in any tissue, mRNA levels of the other MT genes tended to be higher in ALS than in control liver samples, but the differences did not attain statistical significance [20].

Analytical, diagnostic and therapeutic context of MT1B

• The association of MTP and apoB, as assessed in pulse-labeled cells by co-immunoprecipitation, was transient; apoB was prominent on fluorgraphy at 10 min of chase but minimal thereafter [18].
• RESULTS: The mobility at the ankle and first MTP joint were significantly reduced in the foot-at-risk group compared with the diabetic control group and the control subjects (P < 0.0001) [21].
• Twelve male, fasted, anesthetized rhesus monkeys were studied with positron emission tomography (PET) and [11C]alpha-methyl-L-tryptophan (alpha MTP) to determine serotonin synthesis rates as described by Diksic et al [22].
• Median time to tumor progression (MTP) has not yet been attained, but 10-year progression-free survival (PFS) rate was 62% [23].
• These derivatives, MTP and its internal standard were extracted with toluene and determined by gas chromatography with a nitrogen-selective detector [24].

References