Rab7 and Rab27a control two motor protein activities involved in melanosomal transport
| Autor: | Wendy Westbroek, Mieke Mommaas, Jacques Neefjes, J. M. Naeyaert, Jo Lambert, Marjan Huizing, Nuno Rocha, Marije Marsman, Ingrid Jordens |
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| Rok vydání: | 2006 |
| Předmět: |
endocrine system
Clinical Biochemistry Dynein Plant Science GTPase Biology rab27 GTP-Binding Proteins Motor protein Mice Myosin Animals Humans Small GTPase Cytoskeleton Melanosome Melanosomes Pigmentation rab7 GTP-Binding Proteins Biological Transport Cell Biology Cell biology rab GTP-Binding Proteins Melanophilin Rab Agronomy and Crop Science Developmental Biology |
| Zdroj: | Pigment Cell Research. 19:412-423 |
| ISSN: | 1600-0749 0893-5785 |
| Popis: | Melanosomes are lysosome-related organelles that synthesize, store and transport melanin. In epidermal melanocytes, melanosomes mature and are transferred to surrounding keratinocytes, which is essential for skin and coat colour. Mouse coat colour mutants reveal a critical role for the small GTPase Rab27a, which recruits myosin Va through its effector protein melanophilin/Slac2a. Here we have studied how two different Rab GTPases control two motor proteins during subsequent phases in transport of melanosomes. We show that the small GTPase Rab7 mainly associates with early and intermediate stage melanosomes and Rab27a to intermediate and mature melanosomes. Rab27a is found in an active state on mature melanosomes in the tips of the dendrites. The Rab7-Rab7-interacting lysosomal protein-dynein pathway only controls early and intermediate stage melanosomes because the mature melanosomes lack Rab7 and associate with the actin network through Rab27a recruited MyoVa. Thus two Rab proteins regulate two different motor proteins, thereby controlling complementary phases in melanosome biogenesis: Rab7 controls microtubule-mediated transport of early and Rab27a the subsequent actin-dependent transport of mature melanosomes. |
| Databáze: | OpenAIRE |
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