Endo-lysosomal vesicles positive for Rab7 and LAMP1 are terminal vesicles for the transport of dextran.

The endo-lysosomal pathway is essential for intracellular transport and the degradation of extracellular cargo. The relationship between three populations of endo-lysosomal vesicles--Rab7-positive, LAMP1-positive, and both Rab7- and LAMP1-postive--was probed with fluorescence microscopy and single p...

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Main Authors: William H Humphries, Craig J Szymanski, Christine K Payne
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2011-01-01
Series:PLoS ONE
Online Access:http://europepmc.org/articles/PMC3200357?pdf=render
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author William H Humphries
Craig J Szymanski
Christine K Payne
author_facet William H Humphries
Craig J Szymanski
Christine K Payne
author_sort William H Humphries
collection DOAJ
description The endo-lysosomal pathway is essential for intracellular transport and the degradation of extracellular cargo. The relationship between three populations of endo-lysosomal vesicles--Rab7-positive, LAMP1-positive, and both Rab7- and LAMP1-postive--was probed with fluorescence microscopy and single particle tracking. Of specific interest was determining if these vesicles were intermediate or terminal vesicles in the transport of extracellular cargo. We find that the major organelle in the endo-lysosomal pathway, both in terms of population and cargo transport, is positive for Rab7 and LAMP1. Dextran, a fluid phase cargo, shifts from localization within all three populations of vesicles at 30 minutes and 1 hour to primarily LAMP1- and Rab7/LAMP1-vesicles at longer times. This demonstrates that LAMP1- and Rab7/LAMP1-vesicles are terminal vesicles in the endo-lysosomal pathway. We tested two possible mechanisms for this distribution of cargo, delivery to mannose 6-phosphate receptor (M6PR)-negative vesicles and the fusion dynamics of individual vesicles. We find no correlation with M6PR but do find that Rab7-vesicles undergo significantly fewer fusion events than LAMP1- or Rab7/LAMP1-vesicles suggesting that the distribution of fluid phase cargo is driven by vesicle dynamics.
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spelling doaj.art-44b000ec6c834acaaf5d2502cff095562022-12-22T01:29:25ZengPublic Library of Science (PLoS)PLoS ONE1932-62032011-01-01610e2662610.1371/journal.pone.0026626Endo-lysosomal vesicles positive for Rab7 and LAMP1 are terminal vesicles for the transport of dextran.William H HumphriesCraig J SzymanskiChristine K PayneThe endo-lysosomal pathway is essential for intracellular transport and the degradation of extracellular cargo. The relationship between three populations of endo-lysosomal vesicles--Rab7-positive, LAMP1-positive, and both Rab7- and LAMP1-postive--was probed with fluorescence microscopy and single particle tracking. Of specific interest was determining if these vesicles were intermediate or terminal vesicles in the transport of extracellular cargo. We find that the major organelle in the endo-lysosomal pathway, both in terms of population and cargo transport, is positive for Rab7 and LAMP1. Dextran, a fluid phase cargo, shifts from localization within all three populations of vesicles at 30 minutes and 1 hour to primarily LAMP1- and Rab7/LAMP1-vesicles at longer times. This demonstrates that LAMP1- and Rab7/LAMP1-vesicles are terminal vesicles in the endo-lysosomal pathway. We tested two possible mechanisms for this distribution of cargo, delivery to mannose 6-phosphate receptor (M6PR)-negative vesicles and the fusion dynamics of individual vesicles. We find no correlation with M6PR but do find that Rab7-vesicles undergo significantly fewer fusion events than LAMP1- or Rab7/LAMP1-vesicles suggesting that the distribution of fluid phase cargo is driven by vesicle dynamics.http://europepmc.org/articles/PMC3200357?pdf=render
spellingShingle William H Humphries
Craig J Szymanski
Christine K Payne
Endo-lysosomal vesicles positive for Rab7 and LAMP1 are terminal vesicles for the transport of dextran.
PLoS ONE
title Endo-lysosomal vesicles positive for Rab7 and LAMP1 are terminal vesicles for the transport of dextran.
title_full Endo-lysosomal vesicles positive for Rab7 and LAMP1 are terminal vesicles for the transport of dextran.
title_fullStr Endo-lysosomal vesicles positive for Rab7 and LAMP1 are terminal vesicles for the transport of dextran.
title_full_unstemmed Endo-lysosomal vesicles positive for Rab7 and LAMP1 are terminal vesicles for the transport of dextran.
title_short Endo-lysosomal vesicles positive for Rab7 and LAMP1 are terminal vesicles for the transport of dextran.
title_sort endo lysosomal vesicles positive for rab7 and lamp1 are terminal vesicles for the transport of dextran
url http://europepmc.org/articles/PMC3200357?pdf=render
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AT craigjszymanski endolysosomalvesiclespositiveforrab7andlamp1areterminalvesiclesforthetransportofdextran
AT christinekpayne endolysosomalvesiclespositiveforrab7andlamp1areterminalvesiclesforthetransportofdextran