Journal Article

An ER-Localized Form of PV72, a Seed-Specific Vacuolar Sorting Receptor, Interferes the Transport of an NPIR-Containing Proteinase in <i>Arabidopsis</i> Leaves

Etsuko Watanabe, Tomoo Shimada, Kentaro Tamura, Ryo Matsushima, Yasuko Koumoto, Mikio Nishimura and Ikuko Hara-Nishimura

in Plant and Cell Physiology

Published on behalf of Japanese Society of Plant Physiologists

Volume 45, issue 1, pages 9-17
Published in print January 2004 | ISSN: 0032-0781
Published online January 2004 | e-ISSN: 1471-9053 | DOI: http://dx.doi.org/10.1093/pcp/pch012
An ER-Localized Form of PV72, a Seed-Specific Vacuolar Sorting Receptor, Interferes the Transport of an NPIR-Containing Proteinase in Arabidopsis Leaves

More Like This

Show all results sharing these subjects:

  • Biochemistry
  • Molecular and Cell Biology
  • Plant Sciences and Forestry

GO

Show Summary Details

Preview

Putative vacuolar sorting receptors that bind to the vacuolar targeting signals have been found in various plants; pumpkin PV72, pea BP-80 and Arabidopsis AtELP. PV72 is a seed-specific receptor that is predicted to sort seed storage proteins to protein storage vacuoles. Analysis by surface plasmon resonance showed that the lumenal domain of PV72 bound to an NPIR (a typical vacuolar targeting signal)-containing peptide of the precursor of a cysteine proteinase, AtALEU, in the presence of Ca2+ (KD = 0.1 µM). To elucidate the receptor-dependent transport of vacuolar proteins in plant cells, we produced transgenic Arabidopsis plants that expressed a fusion protein (PV72-HDEL) composed of the lumenal domain of PV72 and an endoplasmic reticulum (ER)-retention signal, HDEL. The expression of PV72-HDEL induced the accumulation of the AtALEU precursor. The accumulation level of the AtALEU precursor was dependent on that of PV72-HDEL. In contrast, it did not induce the accumulation of a precursor of another cysteine proteinase, RD21, which contains no NPIR. Detailed subcellular localization revealed that both the AtALEU precursor and PV72-HDEL accumulated in the ER fraction. We found that most of the AtALEU precursor molecules formed a complex with PV72-HDEL. The AtALEU precursor might be trapped by PV72-HDEL in the ER and not transported to the vacuoles. This in-planta analysis supports the hypothesis that an Arabidopsis homolog of PV72 functions as a sorting receptor for the NPIR-containing proteinase. The overall results suggest that vacuolar sorting receptors for the protein storage vacuoles and the lytic vacuoles share the similar recognition mechanism for a vacuolar targeting signal.

Keywords: Keywords: Arabidopsis thaliana — Ligand–receptor interaction — PV72 — Vacuolar proteins — Vacuolar sorting receptor — Vacuolar targeting signal.; Abbreviations: CCV, clathrin-coated vesicle; CTPP, C-terminal propeptide; EGF, epidermal growth factor; ER, endoplasmic reticulum; NTPP, N-terminal propeptide; PA domain, protease-associated domain.

Journal Article.  7566 words.  Illustrated.

Subjects: Biochemistry ; Molecular and Cell Biology ; Plant Sciences and Forestry

Full text: subscription required

How to subscribe Recommend to my Librarian

Users without a subscription are not able to see the full content. Please, subscribe or login to access all content.