Zn2+ depletion blocks endosome fusion

Alejandro Aballay, M. N. Sarrouf, M. I. Colombo, P. D. Stahl, L. S. Mayorga

Research output: Contribution to journalArticle

30 Citations (Scopus)

Abstract

Fusion among endosomes is an important step for transport and sorting of internalized macromolecules. Working in a cell-free system, we previously reported that endosome fusion requires cytosol and ATP, and is sensitive to N-ethylmaleimide. Fusion is regulated by monomeric and heterotrimeric GTP-binding proteins. We now report that fusion can proceed at very low Ca2+ concentrations, i.e. < 30 nM, Moreover, fusion is not affected when intravesicular Ca2+ is depleted by preincubation of vesicles with calcium ionophores (5 μM ionomycin or A23187) in the presence of calcium chelators (5 mM EGTA or 60 mM EDTA). The results indicate that fusion can proceed at extremely low concentrations of intravesicular and extravesicular Ca2+. However, BAPTA [1,2-bis-(o-aminophenoxy)ethane-N,N,N',N'-tetra-acetic acid], a relatively specific Ca2+ chelator, inhibits fusion. BAPTA binds other metals besides Ca2+. We present evidence that BAPTA inhibition is due not to Ca2+ chelation but to Zn2+ depletion. TPEN [N,N,N',N'-tetrakis-(2-pyridylmethyl) ethylenediamine], another metal-ion chelator with low affinity for Ca2+, also inhibited fusion. TPEN- and BAPTA-inhibited fusions were restored by addition of Zn2+. Zn2+-dependent fusion presents the same characteristics as control fusion. In intact cells, TPEN inhibited transport along the endocytic pathway. The results indicate that Zn2+ depletion blocks endosome fusion, suggesting that this ion is necessary for the function of one or more factors involved in the fusion process.

Original languageEnglish (US)
Pages (from-to)919-923
Number of pages5
JournalBiochemical Journal
Volume312
Issue number3
DOIs
StatePublished - Jan 1 1995
Externally publishedYes

Fingerprint

Endosomes
Fusion reactions
Chelating Agents
Metals
Ions
Heterotrimeric GTP-Binding Proteins
Ionomycin
Ethylmaleimide
Ethane
Monomeric GTP-Binding Proteins
Cell-Free System
Calcium Ionophores
Egtazic Acid
Calcimycin
Edetic Acid
Acetic Acid
Cytosol
Adenosine Triphosphate
N,N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine
1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

Cite this

Aballay, A., Sarrouf, M. N., Colombo, M. I., Stahl, P. D., & Mayorga, L. S. (1995). Zn2+ depletion blocks endosome fusion. Biochemical Journal, 312(3), 919-923. https://doi.org/10.1042/bj3120919

Zn2+ depletion blocks endosome fusion. / Aballay, Alejandro; Sarrouf, M. N.; Colombo, M. I.; Stahl, P. D.; Mayorga, L. S.

In: Biochemical Journal, Vol. 312, No. 3, 01.01.1995, p. 919-923.

Research output: Contribution to journalArticle

Aballay, A, Sarrouf, MN, Colombo, MI, Stahl, PD & Mayorga, LS 1995, 'Zn2+ depletion blocks endosome fusion', Biochemical Journal, vol. 312, no. 3, pp. 919-923. https://doi.org/10.1042/bj3120919
Aballay A, Sarrouf MN, Colombo MI, Stahl PD, Mayorga LS. Zn2+ depletion blocks endosome fusion. Biochemical Journal. 1995 Jan 1;312(3):919-923. https://doi.org/10.1042/bj3120919
Aballay, Alejandro ; Sarrouf, M. N. ; Colombo, M. I. ; Stahl, P. D. ; Mayorga, L. S. / Zn2+ depletion blocks endosome fusion. In: Biochemical Journal. 1995 ; Vol. 312, No. 3. pp. 919-923.
@article{befe1c333c3646f7b71dc752740c460f,
title = "Zn2+ depletion blocks endosome fusion",
abstract = "Fusion among endosomes is an important step for transport and sorting of internalized macromolecules. Working in a cell-free system, we previously reported that endosome fusion requires cytosol and ATP, and is sensitive to N-ethylmaleimide. Fusion is regulated by monomeric and heterotrimeric GTP-binding proteins. We now report that fusion can proceed at very low Ca2+ concentrations, i.e. < 30 nM, Moreover, fusion is not affected when intravesicular Ca2+ is depleted by preincubation of vesicles with calcium ionophores (5 μM ionomycin or A23187) in the presence of calcium chelators (5 mM EGTA or 60 mM EDTA). The results indicate that fusion can proceed at extremely low concentrations of intravesicular and extravesicular Ca2+. However, BAPTA [1,2-bis-(o-aminophenoxy)ethane-N,N,N',N'-tetra-acetic acid], a relatively specific Ca2+ chelator, inhibits fusion. BAPTA binds other metals besides Ca2+. We present evidence that BAPTA inhibition is due not to Ca2+ chelation but to Zn2+ depletion. TPEN [N,N,N',N'-tetrakis-(2-pyridylmethyl) ethylenediamine], another metal-ion chelator with low affinity for Ca2+, also inhibited fusion. TPEN- and BAPTA-inhibited fusions were restored by addition of Zn2+. Zn2+-dependent fusion presents the same characteristics as control fusion. In intact cells, TPEN inhibited transport along the endocytic pathway. The results indicate that Zn2+ depletion blocks endosome fusion, suggesting that this ion is necessary for the function of one or more factors involved in the fusion process.",
author = "Alejandro Aballay and Sarrouf, {M. N.} and Colombo, {M. I.} and Stahl, {P. D.} and Mayorga, {L. S.}",
year = "1995",
month = "1",
day = "1",
doi = "10.1042/bj3120919",
language = "English (US)",
volume = "312",
pages = "919--923",
journal = "Biochemical Journal",
issn = "0264-6021",
publisher = "Portland Press Ltd.",
number = "3",

}

TY - JOUR

T1 - Zn2+ depletion blocks endosome fusion

AU - Aballay, Alejandro

AU - Sarrouf, M. N.

AU - Colombo, M. I.

AU - Stahl, P. D.

AU - Mayorga, L. S.

PY - 1995/1/1

Y1 - 1995/1/1

N2 - Fusion among endosomes is an important step for transport and sorting of internalized macromolecules. Working in a cell-free system, we previously reported that endosome fusion requires cytosol and ATP, and is sensitive to N-ethylmaleimide. Fusion is regulated by monomeric and heterotrimeric GTP-binding proteins. We now report that fusion can proceed at very low Ca2+ concentrations, i.e. < 30 nM, Moreover, fusion is not affected when intravesicular Ca2+ is depleted by preincubation of vesicles with calcium ionophores (5 μM ionomycin or A23187) in the presence of calcium chelators (5 mM EGTA or 60 mM EDTA). The results indicate that fusion can proceed at extremely low concentrations of intravesicular and extravesicular Ca2+. However, BAPTA [1,2-bis-(o-aminophenoxy)ethane-N,N,N',N'-tetra-acetic acid], a relatively specific Ca2+ chelator, inhibits fusion. BAPTA binds other metals besides Ca2+. We present evidence that BAPTA inhibition is due not to Ca2+ chelation but to Zn2+ depletion. TPEN [N,N,N',N'-tetrakis-(2-pyridylmethyl) ethylenediamine], another metal-ion chelator with low affinity for Ca2+, also inhibited fusion. TPEN- and BAPTA-inhibited fusions were restored by addition of Zn2+. Zn2+-dependent fusion presents the same characteristics as control fusion. In intact cells, TPEN inhibited transport along the endocytic pathway. The results indicate that Zn2+ depletion blocks endosome fusion, suggesting that this ion is necessary for the function of one or more factors involved in the fusion process.

AB - Fusion among endosomes is an important step for transport and sorting of internalized macromolecules. Working in a cell-free system, we previously reported that endosome fusion requires cytosol and ATP, and is sensitive to N-ethylmaleimide. Fusion is regulated by monomeric and heterotrimeric GTP-binding proteins. We now report that fusion can proceed at very low Ca2+ concentrations, i.e. < 30 nM, Moreover, fusion is not affected when intravesicular Ca2+ is depleted by preincubation of vesicles with calcium ionophores (5 μM ionomycin or A23187) in the presence of calcium chelators (5 mM EGTA or 60 mM EDTA). The results indicate that fusion can proceed at extremely low concentrations of intravesicular and extravesicular Ca2+. However, BAPTA [1,2-bis-(o-aminophenoxy)ethane-N,N,N',N'-tetra-acetic acid], a relatively specific Ca2+ chelator, inhibits fusion. BAPTA binds other metals besides Ca2+. We present evidence that BAPTA inhibition is due not to Ca2+ chelation but to Zn2+ depletion. TPEN [N,N,N',N'-tetrakis-(2-pyridylmethyl) ethylenediamine], another metal-ion chelator with low affinity for Ca2+, also inhibited fusion. TPEN- and BAPTA-inhibited fusions were restored by addition of Zn2+. Zn2+-dependent fusion presents the same characteristics as control fusion. In intact cells, TPEN inhibited transport along the endocytic pathway. The results indicate that Zn2+ depletion blocks endosome fusion, suggesting that this ion is necessary for the function of one or more factors involved in the fusion process.

UR - http://www.scopus.com/inward/record.url?scp=0029416968&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0029416968&partnerID=8YFLogxK

U2 - 10.1042/bj3120919

DO - 10.1042/bj3120919

M3 - Article

C2 - 8554539

AN - SCOPUS:0029416968

VL - 312

SP - 919

EP - 923

JO - Biochemical Journal

JF - Biochemical Journal

SN - 0264-6021

IS - 3

ER -