Document Detail

Synthesis and transport of lysosomal acid phosphatase in normal and I-cell fibroblasts.
MedLine Citation:
PMID:  3160696     Owner:  NLM     Status:  MEDLINE    
The biosynthesis, proteolytic processing, and transport of lysosomal acid phosphatase in normal and I-cell human skin fibroblasts was studied by metabolic labeling of the cells and isolation of acid phosphatase by immunoprecipitation. Several forms of the enzyme were identified in pulse-chase experiments. The largest precursor form had a Mr of 110,000. It was accompanied by several smaller polypeptides (Mr = 84,000-62,000), which were localized to light membranes containing the markers of endoplasmic reticulum and Golgi complex. These polypeptides were further processed to mature forms with apparent Mr of 57,000, 48,000, and 43,000 that accumulated in the cells and were associated with dense lysosomes. Less than 10% of newly synthesized acid phosphatase was secreted mainly as Mr = 112,000 and 74,000 forms. The processing of acid phosphatase was inhibited by NH4Cl and by a peptidyldiazomethyl ketone inhibitor of cysteine proteinases. The intracellular Mr = 110,000, 57,000, and 48,000 and the secreted Mr = 112,000 and 64,000 forms contained phosphorylated oligosaccharides cleavable by endo-beta-N-acetylglucosaminidase H. Transport of acid phosphatase into lysosomes was sensitive to NH4Cl and dependent on mannose 6-phosphate specific receptors by the following criteria: (i) inhibition of endocytosis of acid phosphatase by mannose 6-phosphate, (ii) enhancement of the secretion of acid phosphatase in the presence of antibodies to the mannose 6-phosphatase specific receptor, and (iii) secretion of about two-thirds of newly synthesized acid phosphatase in I-cell fibroblasts. Obviously, the mechanism of transport of acid phosphatase into lysosomes is indistinguishable from that operating for other lysosomal enzymes in fibroblasts. In contrast to other lysosomal enzymes, acid phosphatase appears to be subjected to an early proteolytic processing, presumably within the endoplasmic reticulum, which results in secretion of several processed forms of the enzyme.
P Lemansky; V Gieselmann; A Hasilik; K von Figura
Related Documents :
6234166 - Characterization of the vacuolar atpase activity of the crassulacean-acid-metabolism pl...
2735956 - Inhibition of human erythrocyte and leukocyte aldehyde dehydrogenase activities by diet...
6245876 - Subcellular fractionation of trypanosoma brucei bloodstream forms with special referenc...
3956686 - Effect of halogenmethylenebisphosphonates on bone cells in culture and on bone resorpti...
122566 - The effects of concanavalin a, cerulenin, hydroxyurea and tunicamycin on the incorporat...
1253406 - Simultaneous quantitation of 4-hydroxy-3-methoxymandelic (vanilmandelic) and 4-hydroxy-...
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The Journal of biological chemistry     Volume:  260     ISSN:  0021-9258     ISO Abbreviation:  J. Biol. Chem.     Publication Date:  1985 Jul 
Date Detail:
Created Date:  1985-08-28     Completed Date:  1985-08-28     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  2985121R     Medline TA:  J Biol Chem     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  9023-30     Citation Subset:  IM    
Export Citation:
APA/MLA Format     Download EndNote     Download BibTex
MeSH Terms
Acid Phosphatase / metabolism*
Ammonium Chloride / pharmacology
Biological Transport
Carrier Proteins / physiology
Fibroblasts / enzymology
Lysosomes / enzymology*
Molecular Weight
Mucolipidoses / enzymology*
Oligosaccharides / analysis
Phosphopeptides / analysis
Receptor, IGF Type 2
Reg. No./Substance:
0/Carrier Proteins; 0/Oligosaccharides; 0/Phosphopeptides; 0/Receptor, IGF Type 2; 12125-02-9/Ammonium Chloride; EC Phosphatase

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

Previous Document:  Evidence that platelet and skeletal sarcoplasmic reticulum Ca2+-ATPase are structurally distinct.
Next Document:  An intracellular (ATP + Mg2+)-dependent calcium pump within the N1E-115 neuronal cell line.