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Sphingomyelinase Treatment Induces ATP-independent Endocytosis

ATP hydrolysis has been regarded as a general requirement for internalization processes in mammalian cells. We found, however, that treatment of ATP-depleted macrophages and fibroblasts with exogenous sphingomyelinase (SMase) rapidly induces formation of numerous vesicles that pinch off from the pla...

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Autores principales: Zha, Xiaohui, Pierini, Lynda M., Leopold, Philip L., Skiba, Paul J., Tabas, Ira, Maxfield, Frederick R.
Formato: Texto
Lenguaje:English
Publicado: The Rockefeller University Press 1998
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2132600/
https://www.ncbi.nlm.nih.gov/pubmed/9425152
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author Zha, Xiaohui
Pierini, Lynda M.
Leopold, Philip L.
Skiba, Paul J.
Tabas, Ira
Maxfield, Frederick R.
author_facet Zha, Xiaohui
Pierini, Lynda M.
Leopold, Philip L.
Skiba, Paul J.
Tabas, Ira
Maxfield, Frederick R.
author_sort Zha, Xiaohui
collection PubMed
description ATP hydrolysis has been regarded as a general requirement for internalization processes in mammalian cells. We found, however, that treatment of ATP-depleted macrophages and fibroblasts with exogenous sphingomyelinase (SMase) rapidly induces formation of numerous vesicles that pinch off from the plasma membrane; the process is complete within 10 min after adding SMase. By electron microscopy, the SMase-induced vesicles are ∼400 nm in diameter and lack discernible coats. 15–30% of plasma membrane is internalized by SMase treatment, and there is no detectable enrichment of either clathrin or caveolin in these vesicles. When ATP is restored to the cells, the SMase-induced vesicles are able to deliver fluid-phase markers to late endosomes/lysosomes and return recycling receptors, such as transferrin receptors, back to the plasma membrane. We speculate that hydrolysis of sphingomyelin on the plasma membrane causes inward curvature and subsequent fusion to form sealed vesicles. Many cell types express a SMase that can be secreted or delivered to endosomes and lysosomes. The hydrolysis of sphingomyelin by these enzymes is activated by several signaling pathways, and this may lead to formation of vesicles by the process described here.
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spelling pubmed-21326002008-05-01 Sphingomyelinase Treatment Induces ATP-independent Endocytosis Zha, Xiaohui Pierini, Lynda M. Leopold, Philip L. Skiba, Paul J. Tabas, Ira Maxfield, Frederick R. J Cell Biol Article ATP hydrolysis has been regarded as a general requirement for internalization processes in mammalian cells. We found, however, that treatment of ATP-depleted macrophages and fibroblasts with exogenous sphingomyelinase (SMase) rapidly induces formation of numerous vesicles that pinch off from the plasma membrane; the process is complete within 10 min after adding SMase. By electron microscopy, the SMase-induced vesicles are ∼400 nm in diameter and lack discernible coats. 15–30% of plasma membrane is internalized by SMase treatment, and there is no detectable enrichment of either clathrin or caveolin in these vesicles. When ATP is restored to the cells, the SMase-induced vesicles are able to deliver fluid-phase markers to late endosomes/lysosomes and return recycling receptors, such as transferrin receptors, back to the plasma membrane. We speculate that hydrolysis of sphingomyelin on the plasma membrane causes inward curvature and subsequent fusion to form sealed vesicles. Many cell types express a SMase that can be secreted or delivered to endosomes and lysosomes. The hydrolysis of sphingomyelin by these enzymes is activated by several signaling pathways, and this may lead to formation of vesicles by the process described here. The Rockefeller University Press 1998-01-12 /pmc/articles/PMC2132600/ /pubmed/9425152 Text en This article is distributed under the terms of an Attribution–Noncommercial–Share Alike–No Mirror Sites license for the first six months after the publication date (see http://www.rupress.org/terms). After six months it is available under a Creative Commons License (Attribution–Noncommercial–Share Alike 4.0 Unported license, as described at http://creativecommons.org/licenses/by-nc-sa/4.0/).
spellingShingle Article
Zha, Xiaohui
Pierini, Lynda M.
Leopold, Philip L.
Skiba, Paul J.
Tabas, Ira
Maxfield, Frederick R.
Sphingomyelinase Treatment Induces ATP-independent Endocytosis
title Sphingomyelinase Treatment Induces ATP-independent Endocytosis
title_full Sphingomyelinase Treatment Induces ATP-independent Endocytosis
title_fullStr Sphingomyelinase Treatment Induces ATP-independent Endocytosis
title_full_unstemmed Sphingomyelinase Treatment Induces ATP-independent Endocytosis
title_short Sphingomyelinase Treatment Induces ATP-independent Endocytosis
title_sort sphingomyelinase treatment induces atp-independent endocytosis
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2132600/
https://www.ncbi.nlm.nih.gov/pubmed/9425152
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