Monospecific antipeptide antibodies as a tool to study the intracellular distribution of two homologous forms of cytochrome b

D'Anigo, Antonello; Manera, Ernesto; Longhi, Renato; Borgese, Nica

doi:10.1016/0309-1651(90)90577-l

Cited by 4 publications

(5 citation statements)

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“…In mitochondria tail‐anchored proteins are present in the outer membrane, and like all proteins of this membrane, they are encoded by nuclear DNA, synthesized on cytosolic ribosomes and subsequently transported to their site of function. Tail‐anchored proteins in the mitochondrial outer membrane include: Fis1, a protein involved in fission of mitochondria [3]; three small subunits of the TOM complex (Tom5, Tom6, Tom7) that interact with Tom40 to form the TOM core complex [4–7]; regulators of apoptosis belonging to the Bcl‐2 family [8]; the mitochondrial form of cytochrome b 5 (cyt b 5 ) [9,10]; and an alternatively spliced isoform of vesicle‐associated membrane protein/synaptobrevin (VAMP‐1B) [11].…”

Section: Introductionmentioning

confidence: 99%

Multiple functions of tail‐anchor domains of mitochondrial outer membrane proteins

et al. 2003

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Tail-anchored proteins form a distinct class of membrane proteins that have a single membrane anchor sequence at their C-terminus, the tail-anchor. Their N-terminal portion is exposed to the cytosol. We have studied the roles of tail-anchor domains of proteins residing in the mitochondrial outer membrane. Four distinct functions of the tail-anchor domain were identi¢ed. First, the domain mediates the targeting to mitochondria in a process that probably requires a net positive charge at the C-terminally £anking segment. Second, tail-anchor domains facilitate the insertion into the mitochondrial outer membrane. Third, the tail-anchor is responsible for the assembly of the respective protein into functional multi-subunit complexes; and fourth, tail-anchor domains can stabilize such complexes.

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Section: Introductionmentioning

confidence: 99%

Multiple functions of tail‐anchor domains of mitochondrial outer membrane proteins

et al. 2003

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“…Both are composed of three domains: (a) the amino-terminal hydrophilic domain, (b) the medial hydrophobic domain, and (c) the carboxyl-terminal hydrophilic domain. The amino-terminal domain has about 100 amino acid residues, contains a protoheme, extends out of the membrane, and participates in electron-transferring functions (4,5,13). Sequences of this domain of cyt b 5 and OMb are about 70% identical (14,15).…”

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confidence: 99%

Charged Amino Acids at the Carboxyl-Terminal Portions Determine the Intracellular Locations of Two Isoforms of Cytochromeb 5

Kuroda

Ikenoue

Honsho

et al. 1998

Journal of Biological Chemistry

108

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Outer mitochondrial membrane cytochrome b 5 (OMb), which is an isoform of cytochrome b 5 (cyt b 5 ) in the endoplasmic reticulum, is a typical tail-anchored protein of the outer mitochondrial membrane. We cloned cDNA containing the complete amino acid sequence of OMb and found that the protein has no typical structural feature common to the mitochondrial targeting signal at the amino terminus. To identify the region responsible for the mitochondrial targeting of OMb, various mutated proteins were expressed in cultured mammalian cells, and the subcellular localization of the expressed proteins was analyzed. The deletion of more than 11 amino acid residues from the carboxyl-terminal end of OMb abolished the targeting of the protein to the mitochondria. When the carboxyl-terminal 10 amino acids of OMb were fused to the cyt b 5 that was previously deleted in the corresponding 10 residues, the fused protein localized in the mitochondria, thereby indicating that the carboxyl-terminal 10 amino acid residues of OMb have sufficient information to transport OMb to the mitochondria. The replacement of either of the two positively charged residues within the carboxyl-terminal 10 amino acids by alanine resulted in the transport of the mutant proteins to the endoplasmic reticulum. The mutant cyt b 5 , in which the acidic amino acid in its carboxyl-terminal end was replaced by basic amino acid, could be transported to the mitochondria. It would thus seem that charged amino acids in the carboxylterminal portion of these proteins determine their locations in the cell.

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“…In a previous study, by using monospecific anti-peptide antibodies, we demonstrated that the 2 cyt b5 isoforms have nonoverlapping subcellular distributions and are each located exclusively, or nearly exclusively, on a single target membrane [7]. Homologous proteins with different subcellular localizations are good models for the study of intracellular targeting, because the regions which are less similar between them are good candidates for targeting signals, and because it is possible to construct chimerae which are likely to retain the native structure of the wild-type parent proteins.…”

Section: Introductionmentioning

confidence: 91%

“…The sequence of this domain is 60% identical to the corresponding region of ER bs. Since OM b5 has a higher apparent Mr than the sequenced tryptic fragment and behaves like an integral membrane protein [7], it was anticipated that it would have a membrane-anchoring domain, however, it was not known whether this domain was at the C-or N-terminus of the protein.…”

Section: Introductionmentioning

confidence: 99%

The targeting information of the mitochondrial outer membrane isoform of cytochrome b5 is contained within the carboxyl‐terminal region

Silvestris¹,

D’Arrigo²,

Borgese

1995

FEBS Letters

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Two isoforms of mammalian cytochrome bs, which have homologous cytosolic amino-terminal catalytic domains, are located one on endoplasmic reticulum (ER bs) the other on mitochondrial outer membranes (OM bs). A eDNA coding for the previously unknown carboxyl-terminal domain of OM bs was cloned and a chimera between the catalytic domain of ER bs and the carhoxyl-terminal region of OM bs was expressed in cultured mammlian cells. The chimera localized to mitochondria, indicating that the carhoxyl-terminal 43 amino acids of OM bs contain sufficient information to target the catalytic domain of ER bs to the mitochondrial outer membrane.

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Monospecific antipeptide antibodies as a tool to study the intracellular distribution of two homologous forms of cytochrome b

Cited by 4 publications

References 0 publications

Multiple functions of tail‐anchor domains of mitochondrial outer membrane proteins

Multiple functions of tail‐anchor domains of mitochondrial outer membrane proteins

Charged Amino Acids at the Carboxyl-Terminal Portions Determine the Intracellular Locations of Two Isoforms of Cytochromeb 5

The targeting information of the mitochondrial outer membrane isoform of cytochrome b5 is contained within the carboxyl‐terminal region

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