Latexin, a protein possessing inhibitory activity against rat carboxypeptidase A1 (CPA1) and CPA2, is expressed in a neuronal subset in the cerebral cortex and cells in other neural and non-neural tissues of rat. Although latexin also inhibits mast-cell CPA (MCCPA), the expression of latexin in rat mast cells has not previously been confirmed. In the present study we examined the expression and subcellular localization of latexin in rat peritoneal mast cells. Western blot and reverse-transcriptase-mediated PCR analyses showed that latexin was contained and expressed in the rat peritoneal mast cells. Immunocytochemically, latexin immunofluorescence was localized on granular structures distinct from MCCPA-, histamine- or cathepsin D-immunopositive granules. Immunoelectron microscopy revealed that latexin was associated with a minority population of granules. The latexin-associated granules were separated from MCCPA- or histamine-containing granules on a self-generating density gradient of polyvinylpyrrolidone-coated silica-gel particles (Percoll). Treatments with high ionic strength and heparinase released latexin from the granules, suggesting that latexin is non-covalently associated with a heparin-like component of the granules. MCCPA and histamine were released from the mast cells after non-immunological and immunological stimulation with compound 48/80, A23187 and anti-IgE antibody, whereas latexin was not released. These results show that latexin is synthesized in rat peritoneal mast cells and suggest that it is associated with a unique type of intracellular granules distinct from MCCPA- and histamine-containing secretory granules and lysosomes.
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Research Article|
March 07 2000
Latexin, a carboxypeptidase A inhibitor, is expressed in rat peritoneal mast cells and is associated with granular structures distinct from secretory granules and lysosomes
Yoshihiko URATANI;
Yoshihiko URATANI
1
1To whom correspondence should be addressed (e-mail uraty@libra.ls.m-kagaku.co.jp).
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Keiko TAKIGUCHI-HAYASHI;
Keiko TAKIGUCHI-HAYASHI
1Mitsubishi Kasei Institute of Life Sciences, Machida, Tokyo 194-8511, Japan
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Nobuhiko MIYASAKA;
Nobuhiko MIYASAKA
1Mitsubishi Kasei Institute of Life Sciences, Machida, Tokyo 194-8511, Japan
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Michio SATO;
Michio SATO
1Mitsubishi Kasei Institute of Life Sciences, Machida, Tokyo 194-8511, Japan
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Yasuyoshi ARIMATSU
Yasuyoshi ARIMATSU
1Mitsubishi Kasei Institute of Life Sciences, Machida, Tokyo 194-8511, Japan
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Publisher: Portland Press Ltd
Received:
July 19 1999
Revision Received:
November 23 1999
Accepted:
January 04 2000
Online ISSN: 1470-8728
Print ISSN: 0264-6021
The Biochemical Society, London © 2000
2000
Biochem J (2000) 346 (3): 817–826.
Article history
Received:
July 19 1999
Revision Received:
November 23 1999
Accepted:
January 04 2000
Citation
Yoshihiko URATANI, Keiko TAKIGUCHI-HAYASHI, Nobuhiko MIYASAKA, Michio SATO, Ming-hao JIN, Yasuyoshi ARIMATSU; Latexin, a carboxypeptidase A inhibitor, is expressed in rat peritoneal mast cells and is associated with granular structures distinct from secretory granules and lysosomes. Biochem J 15 March 2000; 346 (3): 817–826. doi: https://doi.org/10.1042/bj3460817
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