title: Proteomic analysis of early melanosomes: identification of novel melanosomal proteins.
abstract: Melanin is a heterogeneous biopolymer produced only by specific cells termed melanocytes, which synthesize and deposit the pigment in specialized membrane-bound organelles known as melanosomes. Although melanosomes have been suspected of being closely related to lysosomes and platelets, the total number of melanosomal proteins is still unknown. Thus far, six melanosome-specific proteins have been identified, and the challenge is to characterize the complete proteome of the melanosome to further understand its mechanism of biogenesis. In this report, we used mass spectrometry and subcellular fractionation to identify protein components of early melanosomes. Using this approach, we have identified all 6 of the known melanosome-specific proteins, 56 proteins that are shared with other organelles, and confirmed the presence of 6 novel melanosomal proteins using western blotting and by immunohistochemistry.
authors.affiliation: Laboratory of Cell Biology, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, USA.
authors.forename: Venkatesha
authors.initials: V
authors.lastname: Basrur
authors.forename: Feng
authors.initials: F
authors.lastname: Yang
authors.forename: Tsuneto
authors.initials: T
authors.lastname: Kushimoto
authors.forename: Youichiro
authors.initials: Y
authors.lastname: Higashimoto
authors.forename: Ken-ichi
authors.initials: K
authors.lastname: Yasumoto
authors.forename: Julio
authors.initials: J
authors.lastname: Valencia
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Muller
authors.forename: Wilfred D
authors.initials: WD
authors.lastname: Vieira
authors.forename: Hidenori
authors.initials: H
authors.lastname: Watabe
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Shabanowitz
authors.forename: Vincent J
authors.initials: VJ
authors.lastname: Hearing
authors.forename: Donald F
authors.initials: DF
authors.lastname: Hunt
authors.forename: Ettore
authors.initials: E
authors.lastname: Appella
mesh_terms: D001792:Blood Platelets / Q000378:metabolism; D015153:Blotting, Western; D002460:Cell Line; D006801:Humans; D007150:Immunohistochemistry; D013058:Mass Spectrometry / Q000379:methods*; D020460:Melanosomes / Q000737:chemistry / Q000378:metabolism* / Q000502:physiology*; D018613:Microscopy, Confocal; D008854:Microscopy, Electron; D008856:Microscopy, Fluorescence; D016253:Microscopy, Immunoelectron; D008954:Models, Biological; D020543:Proteome; D013347:Subcellular Fractions / Q000378:metabolism; D013395:Sucrose / Q000494:pharmacology; D013997:Time Factors
chemical_list: D020543:Proteome; D013395:Sucrose