Central role of the apical membrane H+-ATPase in electrogenesis and epithelial transport in Malpighian tubules

Klaus W. Beyenbach, Thomas L Pannabecker, Wolfram Nagel

Research output: Contribution to journalArticle

52 Citations (Scopus)

Abstract

The effects of bafilomycin A1, a blocker of V-type H+-ATPases, were investigated in Malpighian tubules of Aedes aegypti. Bafilomycin A1 reduced rates of transepithelial fluid secretion and the virtual short-circuit current (vI(sc)) with an IC50 of approximately 5 μmol l-1. As vI(sc) decreased, the electrical resistance increased across the whole epithelium and across the apical membrane, indicating effects on electroconductive pathways. Bafilomycin A1 had no effect when applied from the tubule lumen, pointing to the relative impermeability of the apical membrane of bafilomycin A1. Thus, bafilomycin A1 must take a cytoplasmic route to its blocking site in the proton channel of the H+-ATPase located in the apical membrane of principal cells. The inhibitory effects of bafilomycin A1 were qualitatively similar to those of dinitrophenol in that voltages across the epithelium (V(t)), the basolateral membrane (V(bl)) and the apical membrane (V(a)) depolarized towards zero in parallel. Moreover, V(bl) always tracked V(a), indicating electrical coupling between the two membranes through the shunt. Electrical coupling allows the H+-ATPase to energize not only the apical membrane, but also the basolateral membrane. Furthermore, electrical coupling offers a balance between electroconductive entry of cations across the basolateral membrane and extrusion across the apical membrane to support steady-state conditions during transepithelial transport.

Original languageEnglish (US)
Pages (from-to)1459-1468
Number of pages10
JournalJournal of Experimental Biology
Volume203
Issue number9
StatePublished - May 2000

Fingerprint

Malpighian Tubules
H-transporting ATP synthase
Proton-Translocating ATPases
Malpighian tubules
membrane
Membranes
epithelium
electrical resistance
Aedes aegypti
extrusion
protons
inhibitory concentration 50
cations
secretion
Epithelium
Vacuolar Proton-Translocating ATPases
Dinitrophenols
Fluids and Secretions
Aedes
cells

Keywords

  • Aedes aegypti
  • Apical membrane
  • Bafilomycin
  • Dinitrophenol
  • Insect
  • Mosquito
  • Secretory epithelium
  • Short-circuit current
  • Vacuolar-type H-ATPase

ASJC Scopus subject areas

  • Agricultural and Biological Sciences(all)
  • Agricultural and Biological Sciences (miscellaneous)

Cite this

Central role of the apical membrane H+-ATPase in electrogenesis and epithelial transport in Malpighian tubules. / Beyenbach, Klaus W.; Pannabecker, Thomas L; Nagel, Wolfram.

In: Journal of Experimental Biology, Vol. 203, No. 9, 05.2000, p. 1459-1468.

Research output: Contribution to journalArticle

@article{aea4b237100646c78ad3f764048a1f61,
title = "Central role of the apical membrane H+-ATPase in electrogenesis and epithelial transport in Malpighian tubules",
abstract = "The effects of bafilomycin A1, a blocker of V-type H+-ATPases, were investigated in Malpighian tubules of Aedes aegypti. Bafilomycin A1 reduced rates of transepithelial fluid secretion and the virtual short-circuit current (vI(sc)) with an IC50 of approximately 5 μmol l-1. As vI(sc) decreased, the electrical resistance increased across the whole epithelium and across the apical membrane, indicating effects on electroconductive pathways. Bafilomycin A1 had no effect when applied from the tubule lumen, pointing to the relative impermeability of the apical membrane of bafilomycin A1. Thus, bafilomycin A1 must take a cytoplasmic route to its blocking site in the proton channel of the H+-ATPase located in the apical membrane of principal cells. The inhibitory effects of bafilomycin A1 were qualitatively similar to those of dinitrophenol in that voltages across the epithelium (V(t)), the basolateral membrane (V(bl)) and the apical membrane (V(a)) depolarized towards zero in parallel. Moreover, V(bl) always tracked V(a), indicating electrical coupling between the two membranes through the shunt. Electrical coupling allows the H+-ATPase to energize not only the apical membrane, but also the basolateral membrane. Furthermore, electrical coupling offers a balance between electroconductive entry of cations across the basolateral membrane and extrusion across the apical membrane to support steady-state conditions during transepithelial transport.",
keywords = "Aedes aegypti, Apical membrane, Bafilomycin, Dinitrophenol, Insect, Mosquito, Secretory epithelium, Short-circuit current, Vacuolar-type H-ATPase",
author = "Beyenbach, {Klaus W.} and Pannabecker, {Thomas L} and Wolfram Nagel",
year = "2000",
month = "5",
language = "English (US)",
volume = "203",
pages = "1459--1468",
journal = "Journal of Experimental Biology",
issn = "0022-0949",
publisher = "Company of Biologists Ltd",
number = "9",

}

TY - JOUR

T1 - Central role of the apical membrane H+-ATPase in electrogenesis and epithelial transport in Malpighian tubules

AU - Beyenbach, Klaus W.

AU - Pannabecker, Thomas L

AU - Nagel, Wolfram

PY - 2000/5

Y1 - 2000/5

N2 - The effects of bafilomycin A1, a blocker of V-type H+-ATPases, were investigated in Malpighian tubules of Aedes aegypti. Bafilomycin A1 reduced rates of transepithelial fluid secretion and the virtual short-circuit current (vI(sc)) with an IC50 of approximately 5 μmol l-1. As vI(sc) decreased, the electrical resistance increased across the whole epithelium and across the apical membrane, indicating effects on electroconductive pathways. Bafilomycin A1 had no effect when applied from the tubule lumen, pointing to the relative impermeability of the apical membrane of bafilomycin A1. Thus, bafilomycin A1 must take a cytoplasmic route to its blocking site in the proton channel of the H+-ATPase located in the apical membrane of principal cells. The inhibitory effects of bafilomycin A1 were qualitatively similar to those of dinitrophenol in that voltages across the epithelium (V(t)), the basolateral membrane (V(bl)) and the apical membrane (V(a)) depolarized towards zero in parallel. Moreover, V(bl) always tracked V(a), indicating electrical coupling between the two membranes through the shunt. Electrical coupling allows the H+-ATPase to energize not only the apical membrane, but also the basolateral membrane. Furthermore, electrical coupling offers a balance between electroconductive entry of cations across the basolateral membrane and extrusion across the apical membrane to support steady-state conditions during transepithelial transport.

AB - The effects of bafilomycin A1, a blocker of V-type H+-ATPases, were investigated in Malpighian tubules of Aedes aegypti. Bafilomycin A1 reduced rates of transepithelial fluid secretion and the virtual short-circuit current (vI(sc)) with an IC50 of approximately 5 μmol l-1. As vI(sc) decreased, the electrical resistance increased across the whole epithelium and across the apical membrane, indicating effects on electroconductive pathways. Bafilomycin A1 had no effect when applied from the tubule lumen, pointing to the relative impermeability of the apical membrane of bafilomycin A1. Thus, bafilomycin A1 must take a cytoplasmic route to its blocking site in the proton channel of the H+-ATPase located in the apical membrane of principal cells. The inhibitory effects of bafilomycin A1 were qualitatively similar to those of dinitrophenol in that voltages across the epithelium (V(t)), the basolateral membrane (V(bl)) and the apical membrane (V(a)) depolarized towards zero in parallel. Moreover, V(bl) always tracked V(a), indicating electrical coupling between the two membranes through the shunt. Electrical coupling allows the H+-ATPase to energize not only the apical membrane, but also the basolateral membrane. Furthermore, electrical coupling offers a balance between electroconductive entry of cations across the basolateral membrane and extrusion across the apical membrane to support steady-state conditions during transepithelial transport.

KW - Aedes aegypti

KW - Apical membrane

KW - Bafilomycin

KW - Dinitrophenol

KW - Insect

KW - Mosquito

KW - Secretory epithelium

KW - Short-circuit current

KW - Vacuolar-type H-ATPase

UR - http://www.scopus.com/inward/record.url?scp=0034041747&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0034041747&partnerID=8YFLogxK

M3 - Article

VL - 203

SP - 1459

EP - 1468

JO - Journal of Experimental Biology

JF - Journal of Experimental Biology

SN - 0022-0949

IS - 9

ER -