| Autor: |
Westbroek, Wendy, Lambert, Jo, De Schepper, Sofie, Kleta, Robert, Van Den Bossche, Karolien, Seabra, Miguel C., Huizing, Marjan, Mommaas, Mieke, Naeyaert, Jean Marie |
| Předmět: |
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| Zdroj: |
Pigment Cell Research; Oct2004, Vol. 17 Issue 5, p498-505, 8p, 2 Black and White Photographs, 2 Diagrams, 1 Graph |
| Abstrakt: |
Patients with the autosomal recessiveGriscelli–Pruniérassyndrome type II are immunologically impaired and have an unusual silvery-grey hypopigmented colour of scalp hair, eyelashes and eyebrows but no noteworthy pigmentary abnormalities of the skin. In mostGriscellipatients, theRAB27Agene, which encodes a small GTPase that is associated with the melanosome membrane in melanocytes, is mutated. Here we discuss a genomicRAB27Adeletion found in a 21-month-old MoroccanGriscellipatient. Additionally, we provide evidence that the loss of functional Rab27a in melanocytes of thisGriscellipatient is partially compensated by the up-regulation of Rab27b, a homologue of Rab27a. By real-time quantitative PCR and western blot analysis, we found that Rab27b mRNA and protein, expressed at low levels in normal human melanocytes, is significantly up-regulated in melanocytes derived from this patient. Our immunofluorescence and yeast two-hybrid screening studies reveal that Rab27b can form a tripartite complex on the melanosome membrane with Melanophilin, a Rab27a effector, and protein products of Myosin Va transcripts that contain exon F. Our data suggest that up-regulated Rab27b in melanocytes of theGriscellipatient can partially take over the function of Rab27a, which could explain the fact that this patient had an evenly pigmented skin and was able to tan. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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