scholarly journals Mannose 6-phosphate-independent membrane association of cathepsin D, glucocerebrosidase, and sphingolipid-activating protein in HepG2 cells.

1991 ◽  
Vol 266 (8) ◽  
pp. 4862-4868
Author(s):  
S Rijnboutt ◽  
H M Aerts ◽  
H J Geuze ◽  
J M Tager ◽  
G J Strous
1991 ◽  
Vol 266 (35) ◽  
pp. 23586-23592 ◽  
Author(s):  
S. Rijnboutt ◽  
A.J. Kal ◽  
H.J. Geuze ◽  
H. Aerts ◽  
G.J. Strous

2000 ◽  
Vol 113 (18) ◽  
pp. 3289-3298 ◽  
Author(s):  
A. Dragonetti ◽  
M. Baldassarre ◽  
R. Castino ◽  
M. Demoz ◽  
A. Luini ◽  
...  

Basophils and mast cells contain a peculiar class of inflammatory granules that discharge their content upon antigen-mediated crosslinking of IgE-membrane receptors. The pathways for granule biogenesis and exocytosis in these cells are still largely obscure. In this study we employed the rat basophilic leukemia (RBL)/mast cell line to verify the hypothesis that inflammatory granules share common bioactive molecules and functional properties with lysosomes. We demonstrate that inflammatory granules, as identified by the monoclonal 5G10 antibody (which recognises an integral membrane protein) or by Toluidine Blue staining, have an intralumenal acidic pH, possess lysosomal enzymes and are accessible by fluid-phase and membrane endocytosis markers. In addition, we studied the targeting, subcellular localisation and regulated secretion of the lysosomal aspartic protease cathepsin D (CD) as affected by IgE receptor stimulation in order to obtain information on the pathways for granule biogenesis and exocytosis. Stimulation with DNP-BSA of specific IgE-primed RBL cells led to a prompt release of processed forms of CD, along with other mature lysosomal hydrolases. This release could be prevented by addition of EGTA, indicating that it was dependent on extracellular calcium influx. Antigen stimulation also induced exocytosis of immature CD forms accumulated by ammonium chloride, suggesting the existence of an intermediate station in the pathway for granule biogenesis still sensitive to regulated exocytosis. The targeting of molecules to secretory granules may occur via either a mannose-6-phosphate-dependent or mannose-6-phosphate-independent pathway. We conclude that endosomes and lysosomes in basophils/mast cells can act as regulated secretory granules or actually identify with them.


1996 ◽  
Vol 88 (1-2) ◽  
pp. 82-82
Author(s):  
Valérie LAURENT ◽  
Reza FARNOUD ◽  
Annick LUCAS ◽  
Christian ROUGEOT ◽  
Marcel GARCIA ◽  
...  

2015 ◽  
Vol 1853 (5) ◽  
pp. 1182-1194
Author(s):  
Clara I. Linares ◽  
Gustavo Ferrín ◽  
Patricia Aguilar-Melero ◽  
Sandra González-Rubio ◽  
Manuel Rodríguez-Perálvarez ◽  
...  

1998 ◽  
Vol 140 (5) ◽  
pp. 1075-1089 ◽  
Author(s):  
Barry Press ◽  
Yan Feng ◽  
Bernard Hoflack ◽  
Angela Wandinger-Ness

Stable BHK cell lines inducibly expressing wild-type or dominant negative mutant forms of the rab7 GTPase were isolated and used to analyze the role of a rab7-regulated pathway in lysosome biogenesis. Expression of mutant rab7N125I protein induced a dramatic redistribution of cation-independent mannose 6–phosphate receptor (CI-MPR) from its normal perinuclear localization to large peripheral endosomes. Under these circumstances ∼50% of the total receptor and several lysosomal hydrolases cofractionated with light membranes containing early endosome and Golgi markers. Late endosomes and lysosomes were contained exclusively in well-separated, denser gradient fractions. Newly synthesized CI-MPR and cathepsin D were shown to traverse through an early endocytic compartment, and functional rab7 was crucial for delivery to later compartments. This observation was evidenced by the fact that 2 h after synthesis, both markers were more prevalent in fractions containing light membranes. In addition, both were sensitive to HRP-DAB– mediated cross-linking of early endosomal proteins, and the late endosomal processing of cathepsin D was impaired. Using similar criteria, the lysosomal membrane glycoprotein 120 was not found accumulated in an early endocytic compartment. The data are indicative of a post-Golgi divergence in the routes followed by different lysosome-directed molecules.


2009 ◽  
Vol 90 (5) ◽  
pp. 1093-1103 ◽  
Author(s):  
Atefeh Khakpoor ◽  
Mingkwan Panyasrivanit ◽  
Nitwara Wikan ◽  
Duncan R. Smith

We have recently proposed that amphisomes act as a site for translation and replication of dengue virus (DENV)-2 and that DENV-2 entry and replication are linked through an ongoing association with membranes of an endosomal–autophagosomal lineage. In this report, we present the results of an investigation into the interaction between DENV-3 and the autophagy machinery. Critically, treatment with the lysosomal fusion inhibitor l-asparagine differentiated the interaction of DENV-3 from that of DENV-2. Inhibition of fusion of autophagosomes and amphisomes with lysosomes resulted in decreased DENV-3 production, implying a role for the autophagolysosome in the DENV-3 life cycle. Evidence based upon the co-localization of LC3 and cathepsin D with double stranded RNA and NS1 protein, as assessed by confocal microscopy, support a model in which DENV-3 interacts with both amphisomes and autophagolysosomes. These results demonstrate that the interactions between DENV and the host cell autophagy machinery are complex and may be determined in part by virus-encoded factors.


Author(s):  
Henri Rochefort ◽  
Patrick Augereau ◽  
Pierre Briozzo ◽  
François Capony ◽  
Vincent Cavailles ◽  
...  

SynopsisIn addition to secreted growth factors, acting as autocrine or paracrine mitogens, breast cancer cells secrete other proteins whose function and significance in mammary carcinogenesis may be important. Among them, proteases are particularly interesting since it has been suggested that they play a role in metastatic process, and since at least two of them, the tissue type plasminogen activator and pro-cathepsin D, the precursor of a lysosomal protease, are induced by oestrogens and secreted in excess in some mammary cancer cells.In oestrogen-receptor-positive human breast cancer cell lines (MCF7, ZR75–1), oestrogens stimulate cell proliferation and specifically increase the secretion into the culture medium of a 52,000-dalton (52-kDa) glycoprotein identified as the secreted precursor of a cathepsin D bearing mannose-6-phosphate signals, which is routed to lysosomesviamannose-6-phosphate-IGF-II receptors. We have determined the structure of this procathepsin D by sequencing its complete cDNA sequence, its chromosomal localisation and its transcriptional regulation by oestrogens and other mitogens. In breast cancer cells, pro-cathepsin D production and secretion is much higher and its processing is altered compared to normal mammary epithelial cells in culture.In vitro, pro-cathepsin D acts as an autocrine mitogen on breast cancer cells and can be activated at acidic pH to degrade extracellular matrix, suggesting a role in mediating the effect of oestrogens on tumour growth and invasion. Retrospective clinical studies indicate a significant correlation between high 52-kDa cathepsin D concentrations in the cytosol of primary breast cancer and poor prognosis (Danish Breast Cancer Group, S. Thorpe, Copenhagen). We propose that among the proteases secreted by cancer cells, 52-kDa cathepsin D is important both as a tissue marker in breast cancer and as a potential factor involved in carcinogenesis.


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