Apical and basolateral endocytic pathways of MDCK cells meet in acidic common endosomes distinct from a nearly-neutral apical recycling endosome

Exing Wang, Paul S. Brown, Benjamin Aroeti, Steven J. Chapin, Keith E. Mostov, Kenneth Dunn

Research output: Contribution to journalArticle

115 Citations (Scopus)

Abstract

Quantitative confocal microscopic analyses of living, polarized MDCK ceils demonstrate different pH profiles for apical and basolateral endocytic pathways, despite a rapid and extensive intersection between the two. Three-dimensional characterizations of ligand trafficking demonstrate that the apical and basolateral endocytic pathways share early, acidic compartments distributed throughout the medial regions of the cell. Polar sorting for both pathways occurs in these common endosomes as IgA is sorted from transferrin to alkaline transcytotic vesicles. While transferrin is directly recycled from the common endosomes, IgA is transported to a downstream apical compartment that is nearly neutral in pH. By several criteria this compartment appears to be equivalent to the previously described apical recycling endosome. The functional significance of the abrupt increase in lumenal pH that accompanies IgA sorting is not clear, as disrupting endosome acidification has no effect on polar sorting. These studies provide the first detailed characterizations of endosome acidification in intact polarized cells and clarify the relationship between the apical and basolateral endocytic itineraries of polarized MDCK cells. The extensive mixing of apical and basolateral pathways underscores the importance of endocytic sorting in maintaining the polarity of the plasma membrane of MDCK cells.

Original languageEnglish
Pages (from-to)480-493
Number of pages14
JournalTraffic
Volume1
Issue number6
StatePublished - 2000

Fingerprint

Madin Darby Canine Kidney Cells
Endosomes
Sorting
Recycling
Immunoglobulin A
Acidification
Transferrin
Cell membranes
Ligands
Cell Membrane

Keywords

  • Acidification
  • Endocytosis
  • Endosome
  • Epithelia
  • Immunoglobulin A
  • MDCK
  • Polarity
  • Polymeric Ig receptor
  • Transcytosis
  • Transferrin

ASJC Scopus subject areas

  • Biochemistry
  • Cell Biology
  • Genetics
  • Molecular Biology
  • Structural Biology

Cite this

Apical and basolateral endocytic pathways of MDCK cells meet in acidic common endosomes distinct from a nearly-neutral apical recycling endosome. / Wang, Exing; Brown, Paul S.; Aroeti, Benjamin; Chapin, Steven J.; Mostov, Keith E.; Dunn, Kenneth.

In: Traffic, Vol. 1, No. 6, 2000, p. 480-493.

Research output: Contribution to journalArticle

Wang, Exing ; Brown, Paul S. ; Aroeti, Benjamin ; Chapin, Steven J. ; Mostov, Keith E. ; Dunn, Kenneth. / Apical and basolateral endocytic pathways of MDCK cells meet in acidic common endosomes distinct from a nearly-neutral apical recycling endosome. In: Traffic. 2000 ; Vol. 1, No. 6. pp. 480-493.
@article{c0559b1cf43d417cb14f05724f735ac2,
title = "Apical and basolateral endocytic pathways of MDCK cells meet in acidic common endosomes distinct from a nearly-neutral apical recycling endosome",
abstract = "Quantitative confocal microscopic analyses of living, polarized MDCK ceils demonstrate different pH profiles for apical and basolateral endocytic pathways, despite a rapid and extensive intersection between the two. Three-dimensional characterizations of ligand trafficking demonstrate that the apical and basolateral endocytic pathways share early, acidic compartments distributed throughout the medial regions of the cell. Polar sorting for both pathways occurs in these common endosomes as IgA is sorted from transferrin to alkaline transcytotic vesicles. While transferrin is directly recycled from the common endosomes, IgA is transported to a downstream apical compartment that is nearly neutral in pH. By several criteria this compartment appears to be equivalent to the previously described apical recycling endosome. The functional significance of the abrupt increase in lumenal pH that accompanies IgA sorting is not clear, as disrupting endosome acidification has no effect on polar sorting. These studies provide the first detailed characterizations of endosome acidification in intact polarized cells and clarify the relationship between the apical and basolateral endocytic itineraries of polarized MDCK cells. The extensive mixing of apical and basolateral pathways underscores the importance of endocytic sorting in maintaining the polarity of the plasma membrane of MDCK cells.",
keywords = "Acidification, Endocytosis, Endosome, Epithelia, Immunoglobulin A, MDCK, Polarity, Polymeric Ig receptor, Transcytosis, Transferrin",
author = "Exing Wang and Brown, {Paul S.} and Benjamin Aroeti and Chapin, {Steven J.} and Mostov, {Keith E.} and Kenneth Dunn",
year = "2000",
language = "English",
volume = "1",
pages = "480--493",
journal = "Traffic",
issn = "1398-9219",
publisher = "Blackwell Munksgaard",
number = "6",

}

TY - JOUR

T1 - Apical and basolateral endocytic pathways of MDCK cells meet in acidic common endosomes distinct from a nearly-neutral apical recycling endosome

AU - Wang, Exing

AU - Brown, Paul S.

AU - Aroeti, Benjamin

AU - Chapin, Steven J.

AU - Mostov, Keith E.

AU - Dunn, Kenneth

PY - 2000

Y1 - 2000

N2 - Quantitative confocal microscopic analyses of living, polarized MDCK ceils demonstrate different pH profiles for apical and basolateral endocytic pathways, despite a rapid and extensive intersection between the two. Three-dimensional characterizations of ligand trafficking demonstrate that the apical and basolateral endocytic pathways share early, acidic compartments distributed throughout the medial regions of the cell. Polar sorting for both pathways occurs in these common endosomes as IgA is sorted from transferrin to alkaline transcytotic vesicles. While transferrin is directly recycled from the common endosomes, IgA is transported to a downstream apical compartment that is nearly neutral in pH. By several criteria this compartment appears to be equivalent to the previously described apical recycling endosome. The functional significance of the abrupt increase in lumenal pH that accompanies IgA sorting is not clear, as disrupting endosome acidification has no effect on polar sorting. These studies provide the first detailed characterizations of endosome acidification in intact polarized cells and clarify the relationship between the apical and basolateral endocytic itineraries of polarized MDCK cells. The extensive mixing of apical and basolateral pathways underscores the importance of endocytic sorting in maintaining the polarity of the plasma membrane of MDCK cells.

AB - Quantitative confocal microscopic analyses of living, polarized MDCK ceils demonstrate different pH profiles for apical and basolateral endocytic pathways, despite a rapid and extensive intersection between the two. Three-dimensional characterizations of ligand trafficking demonstrate that the apical and basolateral endocytic pathways share early, acidic compartments distributed throughout the medial regions of the cell. Polar sorting for both pathways occurs in these common endosomes as IgA is sorted from transferrin to alkaline transcytotic vesicles. While transferrin is directly recycled from the common endosomes, IgA is transported to a downstream apical compartment that is nearly neutral in pH. By several criteria this compartment appears to be equivalent to the previously described apical recycling endosome. The functional significance of the abrupt increase in lumenal pH that accompanies IgA sorting is not clear, as disrupting endosome acidification has no effect on polar sorting. These studies provide the first detailed characterizations of endosome acidification in intact polarized cells and clarify the relationship between the apical and basolateral endocytic itineraries of polarized MDCK cells. The extensive mixing of apical and basolateral pathways underscores the importance of endocytic sorting in maintaining the polarity of the plasma membrane of MDCK cells.

KW - Acidification

KW - Endocytosis

KW - Endosome

KW - Epithelia

KW - Immunoglobulin A

KW - MDCK

KW - Polarity

KW - Polymeric Ig receptor

KW - Transcytosis

KW - Transferrin

UR - http://www.scopus.com/inward/record.url?scp=0034208649&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0034208649&partnerID=8YFLogxK

M3 - Article

C2 - 11208134

AN - SCOPUS:0034208649

VL - 1

SP - 480

EP - 493

JO - Traffic

JF - Traffic

SN - 1398-9219

IS - 6

ER -