Disease relevance of ABCB6

• We found that ABCB6 was overexpressed in human hepatocellular carcinomas compared to paired surrounding non-malignant tissue [1].
• We found that there was no difference in ABCB6 gene copy between human liver cancer and its paired non-malignant tissue [1].
• Gangliosides do not affect ABC transporter function in human neuroblastoma cells [2].
• The multidrug resistance (MDR) phenotype, induced by the overexpression of several ABC transporters or by antiapoptotic mechanisms, has been identified as the major cause of drug resistance in the treatment of patients with acute myeloid leukemia (AML) [3].
• Expression and functional activity of the ABC-transporter proteins P-glycoprotein and multidrug-resistance protein 1 in human brain tumor cells and astrocytes [4].

Psychiatry related information on ABCB6

• This review attempts to simplify cardiovascular risk reduction by summarizing key clinical trials in an "ABC" format [5].
• OBJECTIVE: To assess HIV-1 RNA levels and the relationship between HIV-1 reverse transcriptase (RT) genotype from plasma and cerebrospinal fluid (CSF) during treatment with abacavir (Ziagen, ABC) or placebo in combination with stable background therapy (SBG) in subjects with AIDS dementia complex (ADC) (study CNA3001) [6].
• At the age of 6 y, the children were re-assessed by means of the Touwen neurologic assessment, the Movement ABC, and the Child Behavior Check List [7].
• A standardized neuropsychological assessment was conducted, including Kaufman ABC battery, language tests, and motor performance series [8].
• Onset and lifetime prevalence of substance abuse were assessed retrospectively using the IRAOS interview in a population-based, controlled sample of 232 first episodes of schizophrenia (ABC sample) [9].

High impact information on ABCB6

• Current knowledge of CFTR structure and function may help us understand better its mechanism of action, its role in electrolyte transport, its dysfunction in cystic fibrosis, and its relationship to other ABC transporters [10].
• Mutations in a gene encoding an ABC transporter cause pseudoxanthoma elasticum [11].
• This process requires the participation of mitochondria that export a still unknown component via the ISC export machinery, including an ABC transporter [12].
• Although it has been assumed that expression of ABC transporters is responsible for this phenotype, the specific molecules involved have not been defined [13].
• Genome sequencing. The ABC of symbiosis [14].

Chemical compound and disease context of ABCB6

• Here we report the crystal structure at 1.5 A resolution of HisP, the ATP-binding subunit of the histidine permease, which is an ABC transporter from Salmonella typhimurium [15].
• The orotic acid model of hepatocarcinogenesis was used to determine if during stepwise progression to liver cancer, PRP changed with hepatocarcinogenesis [16].
• The serum samples were obtained from infants participating in immunogenicity trials with Hib capsular polysaccharide (PRP) conjugated to meningococcal outer membrane protein complex (PRP-OMPC) or to tetanus toxoid (PRP-T), or PRP oligomers conjugated to a nontoxic mutant diphtheria toxin, CRM197 (Oligo-CRM) [17].
• In particular, we assign the thiamin transporter function to yuaJ in the Bacillus/Clostridium group and the HMP transporter function to an ABC transporter thiXYZ in some proteobacteria and firmicutes [18].
• An ABC-type, high-affinity urea permease identified in cyanobacteria [19].

Biological context of ABCB6

• The ABCB6 gene, involved in iron homeostasis, mitochondrial respiratory function, and maintenance of the stability of mitochondrial DNA, has been positioned to this same chromosomal region, and advocated in literature as a highly probable candidate gene for the syndrome on both functional and positional grounds [20].
• Isolation of a genomic clone containing the promoter region of the human ATP binding cassette (ABC) transporter, ABCB6 [1].
• Polymorphism in a second ABC transporter gene located within the class II region of the human major histocompatibility complex [21].
• We have previously described RING4, a gene within the human MHC class II region that has sequence homology with members of the ABC ("ATP-binding cassette") transporter superfamily [21].
• Within the thermoresistant variants, however, the increase in ABC transporter expression did obviously not influence the MDR phenotype [22].

Anatomical context of ABCB6

• No mutations in the coding region of ABCB6 were found, and the expression level of ABCB6 in patient fibroblasts was found to be comparable to controls [20].
• We also predicted that ABCB6 is functionally linked to haem biosynthesis, because its mRNA is found in both human bone marrow and CD71+ early erythroid cells (by database searching), and because our results show that ABCB6 is highly expressed in human fetal liver, and Abcb6 in mouse embryonic liver [23].
• Here we demonstrate that ABCB6 is uniquely located in the outer mitochondrial membrane and is required for mitochondrial porphyrin uptake [23].
• Cancer cell resistance to chemotherapy is often mediated by overexpression of P-glycoprotein, a plasma membrane ABC (ATP-binding cassette) transporter which extrudes cytotoxic drugs at the expense of ATP hydrolysis [24].
• In conclusion, we confirm the presence of several ABC transporters in the testis and also provide evidence of the presence of Abcb8 in the organ [25].

Associations of ABCB6 with chemical compounds

• Although it could be shown that the overexpressed ABC transporters were functionally active, however, no decreased drug accumulations of doxorubicin, mitoxantrone and rhodamine 123 were observed [22].
• No coordination of constitutive or fenofibrate-induced expression of PXMP1-L with other peroxisomal ABC transporters was observed so that an obligate exclusive heterodimer formation is not likely to occur [26].
• Yet the ABC (ATP binding cassette) transporters are inextricably linked to elements of cholesterol disposition [27].
• Expression of ABC transporters in human hepatocyte carcinoma cells with cross-resistance to epirubicin and mitoxantrone [28].
• These results have potentially important implications in the understanding of the (patho-)physiological roles of MRP1/ABCC1, and possibly other ABC transporter proteins in cellular folate homeostasis and drug resistance [29].

Physical interactions of ABCB6

• It is supposed that these MDR modulators bind into transmembrane domains and the action of ABC transporters is inhibited by induced conformational changes [30].
• The transmembrane ABC-type (ATP binding cassette) half-transporter ABCG2 (BCRP) serves as a marker protein for SP cell selection [31].

Other interactions of ABCB6

• Together, these results show that gangliosides are not relevant to ABC transporter-mediated MDR in neuroblastoma cells [2].
• Genomic organization and chromosomal localization of the human peroxisomal membrane protein-1-like protein (PXMP1-L) gene encoding a peroxisomal ABC transporter [32].
• The ABC (ATP Binding Cassette) is a ubiquitous and important family of such transporter proteins [33].
• We found that the mitochondrial ATP-binding cassette transporter ABCB6 is upregulated (messenger RNA and protein in human and mouse cells) by elevation of cellular porphyrins and postulated that ABCB6 has a function in porphyrin transport [23].
• Based on these data, ABCB6 is not the causative gene for GRACILE syndrome [20].

Analytical, diagnostic and therapeutic context of ABCB6

• Molecular cloning of several rat ABC transporters including a new ABC transporter, Abcb8, and their expression in rat testis [25].
• Southern blot analysis of DNA from the H35 rat hepatoma cells reveals that the PRP gene was amplified compared to normal liver [16].
• PURPOSE: The purpose of this study is to attempt to characterize patients with unfavorable clinical outcome by the relative mRNA levels of ABC transporter expression in their tumor samples and to examine whether relative mRNA levels of each of the ABC transporters can be a useful predictor of progression-free survival in advanced ovarian carcinoma [34].
• We show here that haematopoietic progenitors co-expressing mutant MGMT with an ABC-transporter exhibit resistance to combination chemotherapy in vitro [35].
• Here, using RT-PCR and Western blotting, we investigate other ABC transporters in both normal and tumour human brain tissue and demonstrate the presence of breast cancer resistance protein (BCRP) [36].

References