The ABCA subfamily of ABC transporters includes ten members to date. In this study, we describe an additional gene, ABCA12. Four full-length cDNA sequences have been obtained from human placenta that contain two different polyadenylation sites and two splicing forms, coding for ABCA12 isoforms of 2,595 and 2,516 amino acid residues. Both isoforms are predicted to have two ATP-binding domains (nucleotide binding domain, NBD) and two transmembrane (TM) domains, features shared by all other ABCA subfamily proteins. ABCA12 is most closely related to ABCA1, with an amino acid similarity of 47%. Northern blot analysis demonstrates that a 9.5-kb transcript is mainly expressed in the stom- ach. ABCA12 was mapped to human chromosome 2q34. Two other genes from ABCA subfamily are associated with human inherited diseases, ABCA1 with the cholesterol transport disorders Tangier disease and familial hypoalphalipoproteinemia, and ABCA4 with several retinal degeneration disorders. The ABCA12 gene is located in a region of chromosome 2q34 that harbors the genes for lamellar ichthyosis, polymorphic congenital cataract, and insulin-dependent diabetes mellitus (IDDM13), and therefore is a positional candidate for these pathologies.
The ABCA subfamily of ABC transporters includes ten members to date. In this study, we describe an additional gene, ABCA12. Four full-length cDNA sequences have been obtained from human placenta that contain two different polyadenylation sites and two splicing forms, coding for ABCA12 isoforms of 2,595 and 2,516 amino acid residues. Both isoforms are predicted to have two ATP-binding domains (nucleotide binding domain, NBD) and two transmembrane (TM) domains, features shared by all other ABCA subfamily proteins. ABCA12 is most closely related to ABCA1, with an amino acid similarity of 47%. Northern blot analysis demonstrates that a 9.5-kb transcript is mainly expressed in the stom- ach. ABCA12 was mapped to human chromosome 2q34. Two other genes from ABCA subfamily are associated with human inherited diseases, ABCA1 with the cholesterol transport disorders Tangier disease and familial hypoalphalipoproteinemia, and ABCA4 with several retinal degeneration disorders. The ABCA12 gene is located in a region of chromosome 2q34 that harbors the genes for lamellar ichthyosis, polymorphic congenital cataract, and insulin-dependent diabetes mellitus (IDDM13), and therefore is a positional candidate for these pathologies.
The directed movement of ceramides into, out of or within a cell, or between cells, by means of some agent such as a transporter or pore. Ceramides are a class of lipid composed of sphingosine linked to a fatty acid.
The process in which the cytoplasm of the outermost cells of the vertebrate epidermis is replaced by keratin. Keratinization occurs in the stratum corneum, feathers, hair, claws, nails, hooves, and horns.
The directed movement of lipids into, out of or within a cell, or between cells, by means of some agent such as a transporter or pore. Lipids are compounds soluble in an organic solvent but not, or sparingly, in an aqueous solvent.
Lamellar ichthyosis type 2 (LI2) is a rare autosomal recessive skin disorder for which a gene has been localized on chromosome 2q33-35. We report the identification of five missense mutations in the ABCA12 gene in nine families from Africa affected by LI2. The mutations were homozygous in eight consanguineous families and heterozygous in one non-consanguineous family. Four of these mutations are localized in the first ATP-binding domain (nucleotide-binding fold), which is highly conserved in all ABC proteins. The ABCA12 protein belongs to a superfamily of membrane proteins that translocate a variety of substrates across extra- and intracellular membranes. ABCA transporters have been implicated in several autosomal recessive disorders, notably of lipid metabolism. By analogy with ABCA3, a lamellar body membrane protein in lung alveolar type II cells, ABCA12 could function in cellular lipid trafficking in keratinocytes.
The process whose specific outcome is the progression of the alveolus over time, from its formation to the mature structure. The alveolus is a sac for holding air in the lungs; formed by the terminal dilation of air passageways.
Protein involved in the transport of a molecule (metabolite, protein, etc), a ion or an electron across cell membranes, inside the cell or in a tissue fluid.
A reference proteome is a set of protein sequences derived from a complete proteome which constitutes a defined standard for a particular user community. Reference proteomes are manually defined according to a number of criteria. They cover the proteomes of well- studied model organisms and other proteomes of interest for biomedical and biotechnological research. Reference proteomes have been selected to provide broad coverage of the tree of life, and constitute a representative cross-section of the taxonomic diversity to be found within UniProtKB.