title: Melanocytic galectin-3 is associated with tyrosinase-related protein-1 and pigment biosynthesis.
abstract: Galectin-3 is a family member of the carbohydrate-binding proteins widely expressed by many cell types and exhibits multiple cellular functions. We demonstrate that melanocytes express galectin-3, which is predominantly localized to the cell body peripherally along the Golgi zone. Downregulation of galectin-3 in human melanocytes using short hairpin RNA technology resulted in the reduction of both melanin synthesis and expression/activity of tyrosinase-related protein-1 (Tyrp-1). In the cell body, galectin-3 colocalizes with melanosome-destined cargo, specifically tyrosinase and Tyrp-1. We studied melanocytes cultured from patients with forms of Hermansky-Pudlak syndrome (HPS) containing defects in trafficking steps governed by biogenesis of lysosome-related organelle complex-2 (BLOC-2) (HPS-5), BLOC-3 (HPS-1), and adaptin-3 (HPS-2). We found that galectin-3 expression mimicked the defective expression of the tyrosinase cargo in dendrites of HPS-5 melanocytes, but it was not altered in HPS-1 or HPS-2 melanocytes. In addition, galectin-3 colocalized predominantly with the HPS-5 component of BLOC-2 in normal human melanocytes. These data indicate that galectin-3 is a regulatory component in melanin synthesis affecting the expression of Tyrp-1.
authors: Department of Dermatology, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA.
authors: Allison
authors: A
authors: Chalupa
authors: Department of Dermatology, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA.
authors: Amy
authors: A
authors: Koshoffer
authors: Department of Dermatology, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA.
authors: Emily
authors: E
authors: Galan
authors: Department of Dermatology, School of Medicine, University of California, Davis, Sacramento, California, USA.
authors: Lan
authors: L
authors: Yu
authors: Department of Dermatology, School of Medicine, University of California, Davis, Sacramento, California, USA.
authors: Fu-Tong
authors: FT
authors: Liu
authors: Department of Dermatology, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA. Electronic address: boissyre@ucmail.uc.edu.
authors: Raymond E
authors: RE
authors: Boissy
mesh_terms: D001798:Blood Proteins; D002352:Carrier Proteins / Q000378:metabolism; D002478:Cells, Cultured; D000078404:Epidermal Cells; D004817:Epidermis / Q000378:metabolism; D052816:Foreskin / Q000166:cytology; D037502:Galectin 3 / Q000235:genetics / Q000378:metabolism*; D037161:Galectins; D006056:Golgi Apparatus / Q000378:metabolism; D006801:Humans; D008297:Male; D008543:Melanins / Q000096:biosynthesis*; D008544:Melanocytes / Q000166:cytology / Q000201:enzymology*; D020460:Melanosomes / Q000378:metabolism; D008562:Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism*; D014442:Monophenol Monooxygenase / Q000378:metabolism; D010088:Oxidoreductases / Q000235:genetics / Q000378:metabolism*; D011506:Proteins / Q000378:metabolism; D034741:RNA, Small Interfering / Q000378:metabolism
chemical_list: C492647:BLOC1S2 protein, human; C509457:BLOC1S3 protein, human; D001798:Blood Proteins; D002352:Carrier Proteins; D037502:Galectin 3; D037161:Galectins; C428445:LGALS3 protein, human; D008543:Melanins; D008562:Membrane Glycoproteins; D011506:Proteins; D034741:RNA, Small Interfering; D010088:Oxidoreductases; C489799:TYRP1 protein, human; D014442:Monophenol Monooxygenase