Rab7 and Rab27a control two motor protein activities involved in melanosomal transport.

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.

[1]  T. Fitzpatrick,et al.  Chemical Composition and Terminology Of Specialized Organelles (Melanosomes and Melanin Granules) in Mammalian Melanocytes , 1963, Nature.

[2]  P. Chavrier,et al.  The rab7 GTPase resides on a vesicular compartment connected to lysosomes. , 1995, Journal of cell science.

[3]  A. Wandinger-Ness,et al.  Rab 7: an important regulator of late endocytic membrane traffic , 1995, The Journal of cell biology.

[4]  C. Echeverri,et al.  Molecular characterization of the 50-kD subunit of dynactin reveals function for the complex in chromosome alignment and spindle organization during mitosis , 1996, The Journal of cell biology.

[5]  Vladimir Gelfand,et al.  Regulated bidirectional motility of melanophore pigment granules along microtubules in vitro. , 1997, Proceedings of the National Academy of Sciences of the United States of America.

[6]  Hanry Yu,et al.  Molecular Requirements for Bi-directional Movement of Phagosomes Along Microtubules , 1997, The Journal of cell biology.

[7]  C. Echeverri,et al.  Overexpression of the Dynamitin (p50) Subunit of the Dynactin Complex Disrupts Dynein-dependent Maintenance of Membrane Organelle Distribution , 1997, The Journal of cell biology.

[8]  M. Santillo,et al.  Role of the Small GTPase RAB7 in the Late Endocytic Pathway* , 1997, The Journal of Biological Chemistry.

[9]  G. Enikolopov,et al.  Regulation of Organelle Movement in Melanophores by Protein Kinase A (PKA), Protein Kinase C (PKC), and Protein Phosphatase 2A (PP2A) , 1998, The Journal of cell biology.

[10]  Q. Wei,et al.  Visualization of Melanosome Dynamics within Wild-Type and Dilute Melanocytes Suggests a Paradigm for Myosin V Function In Vivo , 1998, The Journal of cell biology.

[11]  I. Vernos,et al.  Heterotrimeric Kinesin II Is the Microtubule Motor Protein Responsible for Pigment Dispersion in Xenopus Melanophores , 1998, The Journal of cell biology.

[12]  J. Naeyaert,et al.  Myosin V colocalizes with melanosomes and subcortical actin bundles not associated with stress fibers in human epidermal melanocytes. , 1998, The Journal of investigative dermatology.

[13]  B. Goud,et al.  Interaction of a Golgi-associated kinesin-like protein with Rab6. , 1998, Science.

[14]  C. Echeverri,et al.  Opposing motor activities of dynein and kinesin determine retention and transport of MHC class II-containing compartments. , 1999, Journal of cell science.

[15]  E. Cuppen,et al.  A FERM domain governs apical confinement of PTP-BL in epithelial cells. , 1999, Journal of cell science.

[16]  B. Gilchrest,et al.  Role of cytoplasmic dynein in melanosome transport in human melanocytes. , 2000, The Journal of investigative dermatology.

[17]  W. Westbroek,et al.  Colocalization of dynactin subunits P150Glued and P50 with melanosomes in normal human melanocytes. , 2000, Pigment cell research.

[18]  B. Gilchrest,et al.  Kinesin participates in melanosomal movement along melanocyte dendrites. , 2000, The Journal of investigative dermatology.

[19]  A. Fischer,et al.  Mutations in RAB27A cause Griscelli syndrome associated with haemophagocytic syndrome , 2000, Nature Genetics.

[20]  J. Naeyaert,et al.  Cytoplasmic dynein colocalizes with melanosomes in normal human melanocytes , 2000, The British journal of dermatology.

[21]  N. Copeland,et al.  A mutation in Rab27a causes the vesicle transport defects observed in ashen mice. , 2000, Proceedings of the National Academy of Sciences of the United States of America.

[22]  J. Neefjes,et al.  The major substrates for TAP in vivo are derived from newly synthesized proteins , 2000, Nature.

[23]  J. Lambert,et al.  Kinesin and kinectin can associate with the melanosomal surface and form a link with microtubules in normal human melanocytes. , 2000, The Journal of investigative dermatology.

[24]  B. Deurs,et al.  Rab7: a key to lysosome biogenesis. , 2000, Molecular biology of the cell.

[25]  Jacques Neefjes,et al.  The Rab7 effector protein RILP controls lysosomal transport by inducing the recruitment of dynein-dynactin motors , 2001, Current Biology.

[26]  G. Raposo,et al.  Distinct Protein Sorting and Localization to Premelanosomes, Melanosomes, and Lysosomes in Pigmented Melanocytic Cells✪ , 2001, The Journal of cell biology.

[27]  G. Raposo,et al.  Pmel17 initiates premelanosome morphogenesis within multivesicular bodies. , 2001, Molecular biology of the cell.

[28]  M. Mccaffrey,et al.  The small GTPase Rab4A interacts with the central region of cytoplasmic dynein light intermediate chain-1. , 2001, Biochemical and biophysical research communications.

[29]  W. Westbroek,et al.  The dilute locus and Griscelli syndrome: gateways towards a better understanding of melanosome transport. , 2001, Pigment cell research.

[30]  T. Yamashita,et al.  Identification of rab7 as a melanosome-associated protein involved in the intracellular transport of tyrosinase-related protein 1. , 2001, The Journal of investigative dermatology.

[31]  R. Buscà,et al.  Rab27a: A key to melanosome transport in human melanocytes. , 2001, The Journal of cell biology.

[32]  M. Marks,et al.  The melanosome: membrane dynamics in black and white , 2001, Nature Reviews Molecular Cell Biology.

[33]  P. Alifano,et al.  Rab‐interacting lysosomal protein (RILP): the Rab7 effector required for transport to lysosomes , 2001, The EMBO journal.

[34]  L. Collinson,et al.  Rab27a Regulates the Peripheral Distribution of Melanosomes in Melanocytes , 2001, The Journal of cell biology.

[35]  N. Copeland,et al.  Identification of an organelle receptor for myosin-Va , 2002, Nature Cell Biology.

[36]  Chadwick M. Hales,et al.  Rab11 Family Interacting Protein 2 Associates with Myosin Vb and Regulates Plasma Membrane Recycling* , 2002, The Journal of Biological Chemistry.

[37]  K. Mikoshiba,et al.  Slac2-a/Melanophilin, the Missing Link between Rab27 and Myosin Va , 2002, The Journal of Biological Chemistry.

[38]  C. Preisinger,et al.  The Rab6 GTPase Regulates Recruitment of the Dynactin Complex to Golgi Membranes , 2002, Current Biology.

[39]  G. Raposo,et al.  The Dark Side of Lysosome‐Related Organelles: Specialization of the Endocytic Pathway for Melanosome Biogenesis , 2002, Traffic.

[40]  B. Byrne,et al.  A role for regulated binding of p150Glued to microtubule plus ends in organelle transport , 2002, The Journal of cell biology.

[41]  François Darchen,et al.  MyRIP, a novel Rab effector, enables myosin VIIa recruitment to retinal melanosomes , 2002, EMBO reports.

[42]  T. Yamashita,et al.  Tyrosinase and tyrosinase-related protein 1 require Rab7 for their intracellular transport. , 2002, The Journal of investigative dermatology.

[43]  S. Deacon,et al.  Interactions and regulation of molecular motors in Xenopus melanophores , 2002, The Journal of cell biology.

[44]  J. Sellers,et al.  Rab27a is an essential component of melanosome receptor for myosin Va. , 2002, Molecular biology of the cell.

[45]  Alistair N. Hume,et al.  A Family of Rab27-binding Proteins , 2002, The Journal of Biological Chemistry.

[46]  W. Gahl,et al.  Evidence that Griscelli syndrome with neurological involvement is caused by mutations in RAB27A, not MYO5A. , 2002, American journal of human genetics.

[47]  D. Cutler,et al.  Weibel-Palade bodies recruit Rab27 by a content-driven, maturation-dependent mechanism that is independent of cell type , 2003, Journal of Cell Science.

[48]  W. Westbroek,et al.  Characterization of the Molecular Defects in Rab27a, Caused by RAB27A Missense Mutations Found in Patients with Griscelli Syndrome* , 2003, The Journal of Biological Chemistry.

[49]  S. Grinstein,et al.  Phagosomes Fuse with Late Endosomes and/or Lysosomes by Extension of Membrane Protrusions along Microtubules: Role of Rab7 and RILP , 2003, Molecular and Cellular Biology.

[50]  S. Grinstein,et al.  Modulation of Rab5 and Rab7 Recruitment to Phagosomes by Phosphatidylinositol 3-Kinase , 2003, Molecular and Cellular Biology.

[51]  C. Hoogenraad,et al.  Bicaudal D induces selective dynein‐mediated microtubule minus end‐directed transport , 2003, The EMBO journal.

[52]  H. Gomi,et al.  The roles of Rab27 and its effectors in the regulated secretory pathways. , 2003, Cell structure and function.

[53]  V. Hearing,et al.  The Seiji memorial lecture: the melanosome: an ideal model to study cellular differentiation. , 2003, Pigment cell research.

[54]  W. Westbroek,et al.  Interactions of human Myosin Va isoforms, endogenously expressed in human melanocytes, are tightly regulated by the tail domain. , 2003, The Journal of investigative dermatology.

[55]  E. Appella,et al.  Epitope Mapping of the Melanosomal Matrix Protein gp100 (PMEL17) , 2004, Journal of Biological Chemistry.

[56]  I. Jordens,et al.  Dynein-mediated vesicle transport controls intracellular Salmonella replication. , 2004, Molecular biology of the cell.

[57]  E. Caron,et al.  Microtubule motors control membrane dynamics of Salmonella-containing vacuoles , 2004, Journal of Cell Science.

[58]  I. Jordens,et al.  Rab Proteins, Connecting Transport and Vesicle Fusion , 2005, Traffic.

[59]  B. Habermann,et al.  Modulation of Receptor Recycling and Degradation by the Endosomal Kinesin KIF16B , 2005, Cell.

[60]  Y. Kalaidzidis,et al.  Rab Conversion as a Mechanism of Progression from Early to Late Endosomes , 2005, Cell.

[61]  G. Raposo,et al.  The Silver locus product Pmel17/gp100/Silv/ME20: controversial in name and in function. , 2005, Pigment cell research.

[62]  K. Nagashima,et al.  Sorting of Pmel17 to melanosomes through the plasma membrane by AP1 and AP2: evidence for the polarized nature of melanocytes , 2006, Journal of Cell Science.

[63]  G. Raposo,et al.  A lumenal domain-dependent pathway for sorting to intralumenal vesicles of multivesicular endosomes involved in organelle morphogenesis. , 2006, Developmental cell.