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Cited by 126Porphyrin Metabolism and DisordersMitochondrial Function and PathologyDrug Transport and Resistance Mechanisms

The DOI matches its Crossref record.

Involvement of Peripheral-Type Benzodiazepine Receptors in the Intracellular Transport of Heme and Porphyrins1

Taketani, Shigeru, Kohno, Hirao, Furukawa, Takako, Tokunaga, Rikio·1995·The Journal of Biochemistry
DOI 10.1093/oxfordjournals.jbchem.a124790
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Abstract

To investigate the involvement of peripheral-type benzodiazepine receptors (PBR) in heme metabolism, we examined the interaction of [55Fe]heme with PBR. Transfection of the cloned mouse PBR-isoquinoline carboxamide-binding protein (PBR/IBP) cDNA into monkey kidney Cos-1 cells resulted in a 2.5-fold increase in [55Fe]hemin binding sites, concomitant with the increase in [3H]PK11195 binding sites, as compared with those seen in antisense PBR/IBP cDNA-transfected cells. The binding of hemin to the transfected receptors exhibited a relatively high affinity with a Kd of 12 nM, and was inhibited by several benzodiazepine ligands, including PK11195, Ro 5-4864, diazepam and protoporphyrin IX. When mouse liver mitochondria were incubated with [55Fe]hemin, the binding to PBR had a Kd of 15 +/- 1.8 nM. The Bmax of [55Fe]hemin binding to the mitochondria was 6.88 +/- 0.76 pmol/mg of protein, a value consistent with that of [3H]PK11195 binding, with a lower affinity. Coproporphyrinogen III, a precursor porphyrin produced in the cytosol, is translocated into mitochondria, then is converted to protoporphyrinogen IX; this conversion decreased in the presence of benzodiazepine ligands. To examine whether this decrease was related to a decrease in the binding of coproporphyrinogen to the mitochondria, the effects of benzodiazepines on the binding of coproporphyrinogen were examined. As the binding was dose-dependently inhibited by PK11195, Ro 5-4864, and diazepam, porphyrins are likely to be endogenous ligands for PBR. We propose that PBR play a role in the intracellular transport of porphyrins and heme.

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  • The product coproporphyrinogen III is transported to the intermembrane space of mitochondria probably by peripheral-type benzodiazepine receptors (PBR).

    “The product of this reaction – coproporphyrinogen III is transported to the intermembrane space of mitochondria probably by peripheral-type benzodiazepine receptors (PBR) [18,19].”

    From Aminolevulinic Acid (ALA) as a Prodrug in Photodynamic Therapy of Cancer (2011) · cites this paper as [18]

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Metadata

Authors
Taketani, S., Kohno, H., Furukawa, T., & Tokunaga, R.
Affiliations
Kansai Medical University (JP)
Corresponding author
Taketani, Shigeru
Venue
The Journal of Biochemistry
Publisher
Oxford University Press (OUP)
Published
1995-04
Volume
117
Issue
4
Pages
875-880
ISSN
  • 0021-924X (ISSN-L)
  • 1756-2651
DOI
10.1093/oxfordjournals.jbchem.a124790
OpenAlex
W1702029570
Cited by
123
References
0
Citations by year
2025: 3 · 2024: 5 · 2023: 2 · 2022: 1 · 2021: 3 · 2020: 3 · 2019: 1 · 2018: 4 · 2017: 2 · 2016: 6 · 2015: 10 · 2014: 8 · 2013: 5 · 2012: 1
FWCI
0.99
Type
journal article
Language
en
Open access
closed
Locations
  • The Journal of Biochemistry (publishedVersion)
  • PubMed (publishedVersion)
Topics
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Porphyrin Metabolism and Disorders
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Mitochondrial Function and Pathology
  • Health Sciences › Medicine › Oncology › Drug Transport and Resistance Mechanisms
Keywords
translocator protein (TSPO), heme transport, heme metabolism, PK11195, Ro5-4864, diazepam, protoporphyrin IX, coproporphyrinogen III, porphyrin synthesis
MeSH terms
Animals, Binding Sites, Biological Transport, Carrier Proteins, Cells, Cultured, Chlorocebus aethiops, Heme, Hemin, Intracellular Fluid, Iron, Iron Radioisotopes, Kidney, Mitochondria, Liver, Porphyrins, Protoporphyrins, Receptors, GABA-A, Transfection, Mice

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