| First Author | Costin GE | Year | 2005 |
| Journal | Biochem J | Volume | 391 |
| Issue | Pt 2 | Pages | 249-59 |
| PubMed ID | 15960609 | Mgi Jnum | J:117576 |
| Mgi Id | MGI:3696917 | Doi | 10.1042/BJ20042070 |
| Citation | Costin GE, et al. (2005) Mutations in dopachrome tautomerase (Dct) affect eumelanin/pheomelanin synthesis, but do not affect intracellular trafficking of the mutant protein. Biochem J 391(Pt 2):249-59 |
| abstractText | Dopachrome tautomerase (Dct) is a type I membrane protein and an important regulatory enzyme that plays a pivotal role in the biosynthesis of melanin and in the rapid metabolism of its toxic intermediates. Dct-mutant melanocytes carrying the slaty or slaty light mutations were derived from the skin of newborn congenic C57BL/6J non-agouti black mice and were used to study the effect(s) of these mutations on the intracellular trafficking of Dct and on the pigmentation of the cells. Dct activity is 3-fold lower in slaty cells compared with non-agouti black melanocytes, whereas slaty light melanocytes have a surprisingly 28-fold lower Dct activity. Homology modelling of the active site of Dct suggests that the slaty mutation [R194Q (Arg194-->Gln)] is located in the active site and may alter the ability of the enzyme to transform the substrate. Transmembrane prediction methods indicate that the slaty light mutation [G486R (Gly486-->Arg)] may result in the sliding of the transmembrane domain towards the N-terminus, thus interfering with Dct function. Chemical analysis showed that both Dct mutations increase pheomelanin and reduce eumelanin produced by melanocytes in culture. Thus the enzymatic activity of Dct may play a role in determining whether the eumelanin or pheomelanin pathway is preferred for pigment biosynthesis. |
