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Cyclic AMP promotes a peripheral distribution of melanosomes and stimulates melanophilin/Slac2‐a and actin association
Author(s) -
Passeron Thierry,
Bahadoran Philippe,
Bertolotto Corine,
Chiaverini Christine,
Buscà Roser,
Valony Gaëlle,
Bille Karine,
Ortonne JeanPaul,
Ballotti Robert
Publication year - 2004
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fj.03-1240fje
Subject(s) - melanosome , microbiology and biotechnology , actin , organelle , biology , stimulation , chemistry , melanin , endocrinology , biochemistry
ABSTRACT Melanosomes are melanin‐containing organelles that belong to a recently individualized group of lysosome‐related organelles. Recently, numerous reports have dissected the molecular mechanisms that control melanosome transport, but nothing was known about the possible regulation of melanosome distribution by exogenous physiological stimulus. In the present report, we demonstrate that a physiological melanocyte‐differentiating agent such as α‐melanocyte‐stimulating hormone, through the stimulation of the cAMP pathway, induces a rapid centrifugal transport of melanosomes, leading to their accumulation at the dendrite tips of melanocytes. Interestingly, the small GTP binding proteins of the p21Rho family and one of their effectors, p160 Rho‐associated kinase, but not PKA, play a key role in redistribution of melanosomes at the extremities of the dendrites. Further, we have investigated, at the molecular level, the effect of cAMP on the different proteins involved in the control of melanosome transport. We demonstrate that cAMP stimulates the expression of Rab27a and rapidly increases the interaction of the melanophilin/Slac2‐a with actin. Thus, we propose that the stimulation of the interaction between melanophilin/Slac2‐a and actin would allow the rapid accumulation of melanosomes in the actin‐rich region of the dendrite extremities.