Identification of mammalian TOM22 as a subunit of the preprotein translocase of the mitochondrial outer membrane

Kazuko Saeki, Hiroyuki Suzuki, Makoto Tsuneoka, Maki Maeda, Ryo Iwamoto, Hidetoshi Hasuwa, Seiichiro Shida, Tsuyoshi Takahashi, Masao Sakaguchi, Toshiya Endo, Yoshiki Miura, Eisuke Mekada, Katsuyoshi Mihara

Research output: Contribution to journalArticle

35 Citations (Scopus)

Abstract

A mitochondrial outer membrane protein of ~22 kDa (1C9-2) was purified from Vero cells assessing immuno-reactivity with a monoclonal antibody, and the cDNA was cloned based on the partial amino acid sequence of the trypsin-digested fragments. 1C9-2 had 19-20% sequence identity to fungal Tom22, a component of the preprotein translocase of the outer membrane (the TOM complex) with receptor and organizer functions. Despite such a low sequence identity, both shared a remarkable structural similarity in the hydrophobicity profile, membrane topology in the Ncyt-Cin orientation through a transmembrane domain in the middle of the molecule, and the abundant acidic amino acid residues in the N-terminal domain. The antibodies against 1C9-2 inhibited the import of a matrix-targeted preprotein into isolated mitochondria. Blue native polyacrylamide gel electrophoresis of digitonin-solubilized outer membranes revealed that 1C9-2 is firmly associated with TOM40 in the ~400-kDa complex, with a size and composition similar to those of the fungal TOM core complex. Furthermore, 1C9-2 complemented the defects of growth and mitochondrial protein import in Δtom22 yeast cells. Taken together, these results demonstrate that 1C9-2 is a functional homologue of fungal Tom22 and functions as a component of the TOM complex.

Original languageEnglish
Pages (from-to)31996-32002
Number of pages7
JournalJournal of Biological Chemistry
Volume275
Issue number41
Publication statusPublished - 2000 Oct 13
Externally publishedYes

Fingerprint

Mitochondrial Membranes
Membranes
Acidic Amino Acids
Native Polyacrylamide Gel Electrophoresis
Digitonin
Mitochondria
Vero Cells
Mitochondrial Proteins
Hydrophobicity
Electrophoresis
Hydrophobic and Hydrophilic Interactions
Yeast
Trypsin
Amino Acid Sequence
Membrane Proteins
Complementary DNA
Yeasts
Monoclonal Antibodies
Cells
Topology

ASJC Scopus subject areas

  • Biochemistry

Cite this

Saeki, K., Suzuki, H., Tsuneoka, M., Maeda, M., Iwamoto, R., Hasuwa, H., ... Mihara, K. (2000). Identification of mammalian TOM22 as a subunit of the preprotein translocase of the mitochondrial outer membrane. Journal of Biological Chemistry, 275(41), 31996-32002.

Identification of mammalian TOM22 as a subunit of the preprotein translocase of the mitochondrial outer membrane. / Saeki, Kazuko; Suzuki, Hiroyuki; Tsuneoka, Makoto; Maeda, Maki; Iwamoto, Ryo; Hasuwa, Hidetoshi; Shida, Seiichiro; Takahashi, Tsuyoshi; Sakaguchi, Masao; Endo, Toshiya; Miura, Yoshiki; Mekada, Eisuke; Mihara, Katsuyoshi.

In: Journal of Biological Chemistry, Vol. 275, No. 41, 13.10.2000, p. 31996-32002.

Research output: Contribution to journalArticle

Saeki, K, Suzuki, H, Tsuneoka, M, Maeda, M, Iwamoto, R, Hasuwa, H, Shida, S, Takahashi, T, Sakaguchi, M, Endo, T, Miura, Y, Mekada, E & Mihara, K 2000, 'Identification of mammalian TOM22 as a subunit of the preprotein translocase of the mitochondrial outer membrane', Journal of Biological Chemistry, vol. 275, no. 41, pp. 31996-32002.
Saeki, Kazuko ; Suzuki, Hiroyuki ; Tsuneoka, Makoto ; Maeda, Maki ; Iwamoto, Ryo ; Hasuwa, Hidetoshi ; Shida, Seiichiro ; Takahashi, Tsuyoshi ; Sakaguchi, Masao ; Endo, Toshiya ; Miura, Yoshiki ; Mekada, Eisuke ; Mihara, Katsuyoshi. / Identification of mammalian TOM22 as a subunit of the preprotein translocase of the mitochondrial outer membrane. In: Journal of Biological Chemistry. 2000 ; Vol. 275, No. 41. pp. 31996-32002.
@article{9e9079221a2543cba06ad08902a78974,
title = "Identification of mammalian TOM22 as a subunit of the preprotein translocase of the mitochondrial outer membrane",
abstract = "A mitochondrial outer membrane protein of ~22 kDa (1C9-2) was purified from Vero cells assessing immuno-reactivity with a monoclonal antibody, and the cDNA was cloned based on the partial amino acid sequence of the trypsin-digested fragments. 1C9-2 had 19-20{\%} sequence identity to fungal Tom22, a component of the preprotein translocase of the outer membrane (the TOM complex) with receptor and organizer functions. Despite such a low sequence identity, both shared a remarkable structural similarity in the hydrophobicity profile, membrane topology in the Ncyt-Cin orientation through a transmembrane domain in the middle of the molecule, and the abundant acidic amino acid residues in the N-terminal domain. The antibodies against 1C9-2 inhibited the import of a matrix-targeted preprotein into isolated mitochondria. Blue native polyacrylamide gel electrophoresis of digitonin-solubilized outer membranes revealed that 1C9-2 is firmly associated with TOM40 in the ~400-kDa complex, with a size and composition similar to those of the fungal TOM core complex. Furthermore, 1C9-2 complemented the defects of growth and mitochondrial protein import in Δtom22 yeast cells. Taken together, these results demonstrate that 1C9-2 is a functional homologue of fungal Tom22 and functions as a component of the TOM complex.",
author = "Kazuko Saeki and Hiroyuki Suzuki and Makoto Tsuneoka and Maki Maeda and Ryo Iwamoto and Hidetoshi Hasuwa and Seiichiro Shida and Tsuyoshi Takahashi and Masao Sakaguchi and Toshiya Endo and Yoshiki Miura and Eisuke Mekada and Katsuyoshi Mihara",
year = "2000",
month = "10",
day = "13",
language = "English",
volume = "275",
pages = "31996--32002",
journal = "Journal of Biological Chemistry",
issn = "0021-9258",
publisher = "American Society for Biochemistry and Molecular Biology Inc.",
number = "41",

}

TY - JOUR

T1 - Identification of mammalian TOM22 as a subunit of the preprotein translocase of the mitochondrial outer membrane

AU - Saeki, Kazuko

AU - Suzuki, Hiroyuki

AU - Tsuneoka, Makoto

AU - Maeda, Maki

AU - Iwamoto, Ryo

AU - Hasuwa, Hidetoshi

AU - Shida, Seiichiro

AU - Takahashi, Tsuyoshi

AU - Sakaguchi, Masao

AU - Endo, Toshiya

AU - Miura, Yoshiki

AU - Mekada, Eisuke

AU - Mihara, Katsuyoshi

PY - 2000/10/13

Y1 - 2000/10/13

N2 - A mitochondrial outer membrane protein of ~22 kDa (1C9-2) was purified from Vero cells assessing immuno-reactivity with a monoclonal antibody, and the cDNA was cloned based on the partial amino acid sequence of the trypsin-digested fragments. 1C9-2 had 19-20% sequence identity to fungal Tom22, a component of the preprotein translocase of the outer membrane (the TOM complex) with receptor and organizer functions. Despite such a low sequence identity, both shared a remarkable structural similarity in the hydrophobicity profile, membrane topology in the Ncyt-Cin orientation through a transmembrane domain in the middle of the molecule, and the abundant acidic amino acid residues in the N-terminal domain. The antibodies against 1C9-2 inhibited the import of a matrix-targeted preprotein into isolated mitochondria. Blue native polyacrylamide gel electrophoresis of digitonin-solubilized outer membranes revealed that 1C9-2 is firmly associated with TOM40 in the ~400-kDa complex, with a size and composition similar to those of the fungal TOM core complex. Furthermore, 1C9-2 complemented the defects of growth and mitochondrial protein import in Δtom22 yeast cells. Taken together, these results demonstrate that 1C9-2 is a functional homologue of fungal Tom22 and functions as a component of the TOM complex.

AB - A mitochondrial outer membrane protein of ~22 kDa (1C9-2) was purified from Vero cells assessing immuno-reactivity with a monoclonal antibody, and the cDNA was cloned based on the partial amino acid sequence of the trypsin-digested fragments. 1C9-2 had 19-20% sequence identity to fungal Tom22, a component of the preprotein translocase of the outer membrane (the TOM complex) with receptor and organizer functions. Despite such a low sequence identity, both shared a remarkable structural similarity in the hydrophobicity profile, membrane topology in the Ncyt-Cin orientation through a transmembrane domain in the middle of the molecule, and the abundant acidic amino acid residues in the N-terminal domain. The antibodies against 1C9-2 inhibited the import of a matrix-targeted preprotein into isolated mitochondria. Blue native polyacrylamide gel electrophoresis of digitonin-solubilized outer membranes revealed that 1C9-2 is firmly associated with TOM40 in the ~400-kDa complex, with a size and composition similar to those of the fungal TOM core complex. Furthermore, 1C9-2 complemented the defects of growth and mitochondrial protein import in Δtom22 yeast cells. Taken together, these results demonstrate that 1C9-2 is a functional homologue of fungal Tom22 and functions as a component of the TOM complex.

UR - http://www.scopus.com/inward/record.url?scp=0034644647&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0034644647&partnerID=8YFLogxK

M3 - Article

C2 - 10900208

AN - SCOPUS:0034644647

VL - 275

SP - 31996

EP - 32002

JO - Journal of Biological Chemistry

JF - Journal of Biological Chemistry

SN - 0021-9258

IS - 41

ER -