Motifs of VDAC2 required for mitochondrial Bak import and tBid-induced apoptosis

Shamim Naghdi, P. Várnai, György Hajnóczky

Research output: Contribution to journalArticle

33 Citations (Scopus)

Abstract

Voltage-dependent anion channel (VDAC) proteins are major components of the outer mitochondrial membrane. VDAC has three isoforms with >70% sequence similarity and redundant roles in metabolite and ion transport. However, only Vdac2-/-(V2-/-) mice are embryonic lethal, indicating a unique and fundamental function of VDAC2 (V2). Recently, a specific V2 requirement was demonstrated for mitochondrial Bak import and truncated Bid (tBid)-induced apoptosis. To determine the relevant domain(s) of V2 involved, VDAC1 (V1) and V2 chimeric constructs were created and used to rescue V2-/- fibroblasts. Surprisingly, the commonly cited V2-specific N-terminal extension and cysteines were found to be dispensable for Bak import and high tBid sensitivity. In gain-offunction studies, V2 (123-179) was the minimal sequence sufficient to render V1 competent to support Bak insertion. Furthermore, in loss-of-function experiments, T168 and D170 were identified as critical residues. These motifs are conserved in zebrafish V2 (zfV2) that also rescued V2-deficient fibroblasts. Because high-resolution structures of zfV2 and mammalian V1 have become available, we could superimpose these structures and recognized that the critical V2-specific residues help to create a distinctive open "pocket" on the cytoplasmic surface that could facilitate Bak recruitment.

Original languageEnglish
Pages (from-to)E5590-E5599
JournalProceedings of the National Academy of Sciences of the United States of America
Volume112
Issue number41
DOIs
Publication statusPublished - Oct 13 2015

Fingerprint

Voltage-Dependent Anion Channels
Zebrafish
Fibroblasts
Apoptosis
Ion Transport
Mitochondrial Membranes
Cysteine
Protein Isoforms
Proteins

Keywords

  • Apoptosis
  • Bak
  • Mitochondria
  • tBid
  • VDAC2

ASJC Scopus subject areas

  • General

Cite this

Motifs of VDAC2 required for mitochondrial Bak import and tBid-induced apoptosis. / Naghdi, Shamim; Várnai, P.; Hajnóczky, György.

In: Proceedings of the National Academy of Sciences of the United States of America, Vol. 112, No. 41, 13.10.2015, p. E5590-E5599.

Research output: Contribution to journalArticle

@article{7433482e396545238b5d7bf2340c0a3d,
title = "Motifs of VDAC2 required for mitochondrial Bak import and tBid-induced apoptosis",
abstract = "Voltage-dependent anion channel (VDAC) proteins are major components of the outer mitochondrial membrane. VDAC has three isoforms with >70{\%} sequence similarity and redundant roles in metabolite and ion transport. However, only Vdac2-/-(V2-/-) mice are embryonic lethal, indicating a unique and fundamental function of VDAC2 (V2). Recently, a specific V2 requirement was demonstrated for mitochondrial Bak import and truncated Bid (tBid)-induced apoptosis. To determine the relevant domain(s) of V2 involved, VDAC1 (V1) and V2 chimeric constructs were created and used to rescue V2-/- fibroblasts. Surprisingly, the commonly cited V2-specific N-terminal extension and cysteines were found to be dispensable for Bak import and high tBid sensitivity. In gain-offunction studies, V2 (123-179) was the minimal sequence sufficient to render V1 competent to support Bak insertion. Furthermore, in loss-of-function experiments, T168 and D170 were identified as critical residues. These motifs are conserved in zebrafish V2 (zfV2) that also rescued V2-deficient fibroblasts. Because high-resolution structures of zfV2 and mammalian V1 have become available, we could superimpose these structures and recognized that the critical V2-specific residues help to create a distinctive open {"}pocket{"} on the cytoplasmic surface that could facilitate Bak recruitment.",
keywords = "Apoptosis, Bak, Mitochondria, tBid, VDAC2",
author = "Shamim Naghdi and P. V{\'a}rnai and Gy{\"o}rgy Hajn{\'o}czky",
year = "2015",
month = "10",
day = "13",
doi = "10.1073/pnas.1510574112",
language = "English",
volume = "112",
pages = "E5590--E5599",
journal = "Proceedings of the National Academy of Sciences of the United States of America",
issn = "0027-8424",
number = "41",

}

TY - JOUR

T1 - Motifs of VDAC2 required for mitochondrial Bak import and tBid-induced apoptosis

AU - Naghdi, Shamim

AU - Várnai, P.

AU - Hajnóczky, György

PY - 2015/10/13

Y1 - 2015/10/13

N2 - Voltage-dependent anion channel (VDAC) proteins are major components of the outer mitochondrial membrane. VDAC has three isoforms with >70% sequence similarity and redundant roles in metabolite and ion transport. However, only Vdac2-/-(V2-/-) mice are embryonic lethal, indicating a unique and fundamental function of VDAC2 (V2). Recently, a specific V2 requirement was demonstrated for mitochondrial Bak import and truncated Bid (tBid)-induced apoptosis. To determine the relevant domain(s) of V2 involved, VDAC1 (V1) and V2 chimeric constructs were created and used to rescue V2-/- fibroblasts. Surprisingly, the commonly cited V2-specific N-terminal extension and cysteines were found to be dispensable for Bak import and high tBid sensitivity. In gain-offunction studies, V2 (123-179) was the minimal sequence sufficient to render V1 competent to support Bak insertion. Furthermore, in loss-of-function experiments, T168 and D170 were identified as critical residues. These motifs are conserved in zebrafish V2 (zfV2) that also rescued V2-deficient fibroblasts. Because high-resolution structures of zfV2 and mammalian V1 have become available, we could superimpose these structures and recognized that the critical V2-specific residues help to create a distinctive open "pocket" on the cytoplasmic surface that could facilitate Bak recruitment.

AB - Voltage-dependent anion channel (VDAC) proteins are major components of the outer mitochondrial membrane. VDAC has three isoforms with >70% sequence similarity and redundant roles in metabolite and ion transport. However, only Vdac2-/-(V2-/-) mice are embryonic lethal, indicating a unique and fundamental function of VDAC2 (V2). Recently, a specific V2 requirement was demonstrated for mitochondrial Bak import and truncated Bid (tBid)-induced apoptosis. To determine the relevant domain(s) of V2 involved, VDAC1 (V1) and V2 chimeric constructs were created and used to rescue V2-/- fibroblasts. Surprisingly, the commonly cited V2-specific N-terminal extension and cysteines were found to be dispensable for Bak import and high tBid sensitivity. In gain-offunction studies, V2 (123-179) was the minimal sequence sufficient to render V1 competent to support Bak insertion. Furthermore, in loss-of-function experiments, T168 and D170 were identified as critical residues. These motifs are conserved in zebrafish V2 (zfV2) that also rescued V2-deficient fibroblasts. Because high-resolution structures of zfV2 and mammalian V1 have become available, we could superimpose these structures and recognized that the critical V2-specific residues help to create a distinctive open "pocket" on the cytoplasmic surface that could facilitate Bak recruitment.

KW - Apoptosis

KW - Bak

KW - Mitochondria

KW - tBid

KW - VDAC2

UR - http://www.scopus.com/inward/record.url?scp=84944088968&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84944088968&partnerID=8YFLogxK

U2 - 10.1073/pnas.1510574112

DO - 10.1073/pnas.1510574112

M3 - Article

C2 - 26417093

AN - SCOPUS:84944088968

VL - 112

SP - E5590-E5599

JO - Proceedings of the National Academy of Sciences of the United States of America

JF - Proceedings of the National Academy of Sciences of the United States of America

SN - 0027-8424

IS - 41

ER -