Patch clamp studies of single intact secretory granules

Andres Oberhauser, J. M. Fernandez

Research output: Contribution to journalArticle

17 Citations (Scopus)

Abstract

The membrane of secretory granules is involved in the molecular events that cause exocytotic fusion. Several of the proteins that have been purified from the membrane of secretory granules form ion channels when they are reconstituted in lipid bilayers and, therefore, have been thought to form part of the molecular structure of the exocytotic fusion pore. We have used the patch clamp technique to study ion conductances in single isolated secretory granules from beige mouse mast cells. We found that the membrane of the intact granule had a conductance of <50 pS. No abrupt changes in current corresponding to the opening and closing of ion channels were observed, even under conditions where exocytotic fusion occurred. However, mechanical tension or a large voltage pulse caused the breakdown of the granule membrane resulting in the abrupt opening of a pore with an ion conductance of about 1 nS that fluctuated rapidly and could expand to an immeasurably large conductance or close completely. Surprisingly, the behavior of these pores resembled the pattern of conductance changes of exocytotic fusion pores observed in degranulating beige mast cells. This similarity supports the view that the earliest fusion pore is formed upon the breakdown of a bilayer such as that formed during hemifusion.

Original languageEnglish (US)
Pages (from-to)1844-1852
Number of pages9
JournalBiophysical Journal
Volume65
Issue number5
StatePublished - 1993
Externally publishedYes

Fingerprint

Secretory Vesicles
Membranes
Ion Channels
Mast Cells
Ions
Lipid Bilayers
Patch-Clamp Techniques
Molecular Structure
Proteins

ASJC Scopus subject areas

  • Biophysics

Cite this

Patch clamp studies of single intact secretory granules. / Oberhauser, Andres; Fernandez, J. M.

In: Biophysical Journal, Vol. 65, No. 5, 1993, p. 1844-1852.

Research output: Contribution to journalArticle

Oberhauser, A & Fernandez, JM 1993, 'Patch clamp studies of single intact secretory granules', Biophysical Journal, vol. 65, no. 5, pp. 1844-1852.
Oberhauser, Andres ; Fernandez, J. M. / Patch clamp studies of single intact secretory granules. In: Biophysical Journal. 1993 ; Vol. 65, No. 5. pp. 1844-1852.
@article{faaa8e55049246eca5a8c9e4f656df6a,
title = "Patch clamp studies of single intact secretory granules",
abstract = "The membrane of secretory granules is involved in the molecular events that cause exocytotic fusion. Several of the proteins that have been purified from the membrane of secretory granules form ion channels when they are reconstituted in lipid bilayers and, therefore, have been thought to form part of the molecular structure of the exocytotic fusion pore. We have used the patch clamp technique to study ion conductances in single isolated secretory granules from beige mouse mast cells. We found that the membrane of the intact granule had a conductance of <50 pS. No abrupt changes in current corresponding to the opening and closing of ion channels were observed, even under conditions where exocytotic fusion occurred. However, mechanical tension or a large voltage pulse caused the breakdown of the granule membrane resulting in the abrupt opening of a pore with an ion conductance of about 1 nS that fluctuated rapidly and could expand to an immeasurably large conductance or close completely. Surprisingly, the behavior of these pores resembled the pattern of conductance changes of exocytotic fusion pores observed in degranulating beige mast cells. This similarity supports the view that the earliest fusion pore is formed upon the breakdown of a bilayer such as that formed during hemifusion.",
author = "Andres Oberhauser and Fernandez, {J. M.}",
year = "1993",
language = "English (US)",
volume = "65",
pages = "1844--1852",
journal = "Biophysical Journal",
issn = "0006-3495",
publisher = "Biophysical Society",
number = "5",

}

TY - JOUR

T1 - Patch clamp studies of single intact secretory granules

AU - Oberhauser, Andres

AU - Fernandez, J. M.

PY - 1993

Y1 - 1993

N2 - The membrane of secretory granules is involved in the molecular events that cause exocytotic fusion. Several of the proteins that have been purified from the membrane of secretory granules form ion channels when they are reconstituted in lipid bilayers and, therefore, have been thought to form part of the molecular structure of the exocytotic fusion pore. We have used the patch clamp technique to study ion conductances in single isolated secretory granules from beige mouse mast cells. We found that the membrane of the intact granule had a conductance of <50 pS. No abrupt changes in current corresponding to the opening and closing of ion channels were observed, even under conditions where exocytotic fusion occurred. However, mechanical tension or a large voltage pulse caused the breakdown of the granule membrane resulting in the abrupt opening of a pore with an ion conductance of about 1 nS that fluctuated rapidly and could expand to an immeasurably large conductance or close completely. Surprisingly, the behavior of these pores resembled the pattern of conductance changes of exocytotic fusion pores observed in degranulating beige mast cells. This similarity supports the view that the earliest fusion pore is formed upon the breakdown of a bilayer such as that formed during hemifusion.

AB - The membrane of secretory granules is involved in the molecular events that cause exocytotic fusion. Several of the proteins that have been purified from the membrane of secretory granules form ion channels when they are reconstituted in lipid bilayers and, therefore, have been thought to form part of the molecular structure of the exocytotic fusion pore. We have used the patch clamp technique to study ion conductances in single isolated secretory granules from beige mouse mast cells. We found that the membrane of the intact granule had a conductance of <50 pS. No abrupt changes in current corresponding to the opening and closing of ion channels were observed, even under conditions where exocytotic fusion occurred. However, mechanical tension or a large voltage pulse caused the breakdown of the granule membrane resulting in the abrupt opening of a pore with an ion conductance of about 1 nS that fluctuated rapidly and could expand to an immeasurably large conductance or close completely. Surprisingly, the behavior of these pores resembled the pattern of conductance changes of exocytotic fusion pores observed in degranulating beige mast cells. This similarity supports the view that the earliest fusion pore is formed upon the breakdown of a bilayer such as that formed during hemifusion.

UR - http://www.scopus.com/inward/record.url?scp=0027524726&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0027524726&partnerID=8YFLogxK

M3 - Article

VL - 65

SP - 1844

EP - 1852

JO - Biophysical Journal

JF - Biophysical Journal

SN - 0006-3495

IS - 5

ER -