Abstract
The protein product of the ocular albinism type 1 gene, named OA1, is a pigment cell-specific G protein-coupled receptor exclusively localized to intracellular organelles, namely lysosomes and melanosomes. Loss of OA1 function leads to the formation of macromelanosomes, suggesting that this receptor is implicated in organelle biogenesis, however the mechanism involved in the pathogenesis of the disease remains obscure. We report here the identification of an unexpected abnormality in melanosome distribution both in retinal pigment epithelium (RPE) and skin melanocytes of Oa1-knock-out (KO) mice, consisting in a displacement of the organelles from the central cytoplasm towards the cell periphery. Despite their depletion from the microtubule (MT)-enriched perinuclear region, Oa1-KO melanosomes were able to aggregate at the centrosome upon disruption of the actin cytoskeleton or expression of a dominant-negative construct of myosin Va. Consistently, quantification of organelle transport in living cells revealed that Oa1-KO melanosomes displayed a severe reduction in MT-based motility; however, this defect was rescued to normal following inhibition of actin-dependent capture at the cell periphery. Together, these data point to a defective regulation of organelle transport in the absence of OA1 and imply that the cytoskeleton might represent a downstream effector of this receptor. Furthermore, our results enlighten a novel function for OA1 in pigment cells and suggest that ocular albinism type 1 might result from a different pathogenetic mechanism than previously thought, based on an organelle-autonomous signalling pathway implicated in the regulation of both membrane traffic and transport.
| Original language | English |
|---|---|
| Pages (from-to) | 3487-3501 |
| Number of pages | 15 |
| Journal | Human Molecular Genetics |
| Volume | 17 |
| Issue number | 22 |
| DOIs | |
| Publication status | Published - 2008 |
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ASJC Scopus subject areas
- Genetics
- Genetics(clinical)
- Molecular Biology
Cite this
The ocular albinism type 1 protein, an intracellular G protein-coupled receptor, regulates melanosome transport in pigment cells. / Palmisano, Ilaria; Bagnato, Paola; Palmigiano, Angela; Innamorati, Giulio; Rotondo, Giuseppe; Altimare, Domenico; Venturi, Consuelo; Sviderskaya, Elena V.; Piccirillo, Rosanna; Coppola, Massimiliano; Marigo, Valeria; Incerti, Barbara; Ballabio, Andrea; Surace, Enrico M.; Tacchetti, Carlo; Bennett, Dorothy C.; Schiaffino, Maria Vittoria.
In: Human Molecular Genetics, Vol. 17, No. 22, 2008, p. 3487-3501.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - The ocular albinism type 1 protein, an intracellular G protein-coupled receptor, regulates melanosome transport in pigment cells
AU - Palmisano, Ilaria
AU - Bagnato, Paola
AU - Palmigiano, Angela
AU - Innamorati, Giulio
AU - Rotondo, Giuseppe
AU - Altimare, Domenico
AU - Venturi, Consuelo
AU - Sviderskaya, Elena V.
AU - Piccirillo, Rosanna
AU - Coppola, Massimiliano
AU - Marigo, Valeria
AU - Incerti, Barbara
AU - Ballabio, Andrea
AU - Surace, Enrico M.
AU - Tacchetti, Carlo
AU - Bennett, Dorothy C.
AU - Schiaffino, Maria Vittoria
PY - 2008
Y1 - 2008
N2 - The protein product of the ocular albinism type 1 gene, named OA1, is a pigment cell-specific G protein-coupled receptor exclusively localized to intracellular organelles, namely lysosomes and melanosomes. Loss of OA1 function leads to the formation of macromelanosomes, suggesting that this receptor is implicated in organelle biogenesis, however the mechanism involved in the pathogenesis of the disease remains obscure. We report here the identification of an unexpected abnormality in melanosome distribution both in retinal pigment epithelium (RPE) and skin melanocytes of Oa1-knock-out (KO) mice, consisting in a displacement of the organelles from the central cytoplasm towards the cell periphery. Despite their depletion from the microtubule (MT)-enriched perinuclear region, Oa1-KO melanosomes were able to aggregate at the centrosome upon disruption of the actin cytoskeleton or expression of a dominant-negative construct of myosin Va. Consistently, quantification of organelle transport in living cells revealed that Oa1-KO melanosomes displayed a severe reduction in MT-based motility; however, this defect was rescued to normal following inhibition of actin-dependent capture at the cell periphery. Together, these data point to a defective regulation of organelle transport in the absence of OA1 and imply that the cytoskeleton might represent a downstream effector of this receptor. Furthermore, our results enlighten a novel function for OA1 in pigment cells and suggest that ocular albinism type 1 might result from a different pathogenetic mechanism than previously thought, based on an organelle-autonomous signalling pathway implicated in the regulation of both membrane traffic and transport.
AB - The protein product of the ocular albinism type 1 gene, named OA1, is a pigment cell-specific G protein-coupled receptor exclusively localized to intracellular organelles, namely lysosomes and melanosomes. Loss of OA1 function leads to the formation of macromelanosomes, suggesting that this receptor is implicated in organelle biogenesis, however the mechanism involved in the pathogenesis of the disease remains obscure. We report here the identification of an unexpected abnormality in melanosome distribution both in retinal pigment epithelium (RPE) and skin melanocytes of Oa1-knock-out (KO) mice, consisting in a displacement of the organelles from the central cytoplasm towards the cell periphery. Despite their depletion from the microtubule (MT)-enriched perinuclear region, Oa1-KO melanosomes were able to aggregate at the centrosome upon disruption of the actin cytoskeleton or expression of a dominant-negative construct of myosin Va. Consistently, quantification of organelle transport in living cells revealed that Oa1-KO melanosomes displayed a severe reduction in MT-based motility; however, this defect was rescued to normal following inhibition of actin-dependent capture at the cell periphery. Together, these data point to a defective regulation of organelle transport in the absence of OA1 and imply that the cytoskeleton might represent a downstream effector of this receptor. Furthermore, our results enlighten a novel function for OA1 in pigment cells and suggest that ocular albinism type 1 might result from a different pathogenetic mechanism than previously thought, based on an organelle-autonomous signalling pathway implicated in the regulation of both membrane traffic and transport.
UR - http://www.scopus.com/inward/record.url?scp=54949125380&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=54949125380&partnerID=8YFLogxK
U2 - 10.1093/hmg/ddn241
DO - 10.1093/hmg/ddn241
M3 - Article
C2 - 18697795
AN - SCOPUS:54949125380
VL - 17
SP - 3487
EP - 3501
JO - Human Molecular Genetics
JF - Human Molecular Genetics
SN - 0964-6906
IS - 22
ER -