Document Detail

Sialylated core 1 O-glycans influence the sorting of Pmel17/gp100 and determine its capacity to form fibrils.
MedLine Citation:
PMID:  17303571     Owner:  NLM     Status:  MEDLINE    
Pmel17 is a melanocyte/melanoma-specific protein that is essential for the maturation of melanosomes to form mature, fibrillar, and pigmented organelles. Recently, we reported that the less glycosylated form of Pmel17 (termed iPmel17) is sorted via the plasma membrane in a manner distinct from mature Pmel17 (termed mPmel17), which is sorted directly to melanosomes. To clarify the mechanism(s) underlying the distinct processing and sorting of Pmel17, we generated a highly specific antibody (termed alphaPEP25h) against an epitope within the repeat domain of Pmel17 that is sensitive to changes in O-glycosylation. alphaPEP25h recognizes only iPmel17 and allows analysis of the processing and sorting of iPmel17 when compared with alphaPEP13h, an antibody that recognizes both iPmel17 and mPmel17. Our novel findings using alphaPEP25h demonstrate that iPmel17 differs from mPmel17 not only in its sensitivity to endoglycosidase H, but also in the content of core 1 O-glycans modified with sialic acid. This evidence reveals that iPmel17 is glycosylated differently in the Golgi and that it is sorted through the secretory pathway. Analysis of Pmel17 processing in glycosylation-deficient mutant cells reveals that Pmel17 lacking the correct addition of sialic acid and galactose loses the ability to form fibrils. Furthermore, we show that addition of sialic acid affects the stability and sorting of Pmel17 and reduces pigmentation. Alterations in sialyltransferase activity and substrates differ between normal and transformed melanocytes and may represent a critical change during malignant transformation.
Julio C Valencia; Francois Rouzaud; Sylvain Julien; Kevin G Chen; Thierry Passeron; Yuji Yamaguchi; Mones Abu-Asab; Maria Tsokos; Gertrude E Costin; Hiroshi Yamaguchi; Lisa M Miller Jenkins; Kunio Nagashima; Ettore Appella; Vincent J Hearing
Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Intramural     Date:  2007-02-15
Journal Detail:
Title:  The Journal of biological chemistry     Volume:  282     ISSN:  0021-9258     ISO Abbreviation:  J. Biol. Chem.     Publication Date:  2007 Apr 
Date Detail:
Created Date:  2007-04-09     Completed Date:  2007-05-31     Revised Date:  2012-03-02    
Medline Journal Info:
Nlm Unique ID:  2985121R     Medline TA:  J Biol Chem     Country:  United States    
Other Details:
Languages:  eng     Pagination:  11266-80     Citation Subset:  IM    
Laboratory of Cell Biology, NCI, National Institutes of Health, Bethesda, Maryland 20892, USA.
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MeSH Terms
Antibodies / immunology
Cell Line, Tumor
Endoplasmic Reticulum / metabolism
Melanosomes / metabolism
Membrane Glycoproteins / chemistry,  genetics,  immunology,  metabolism*
Microscopy, Immunoelectron
N-Acetylneuraminic Acid / metabolism
Polysaccharides / metabolism*
Protein Transport
Time Factors
gp100 Melanoma Antigen
Grant Support
Reg. No./Substance:
0/Antibodies; 0/Membrane Glycoproteins; 0/PMEL protein, human; 0/Polysaccharides; 0/gp100 Melanoma Antigen; 131-48-6/N-Acetylneuraminic Acid

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