Journal Article

Sucrose-Controlled Transport and Turnover of <i>α</i>-Amylase in Rice (<i>Oryza sativa</i> L.) Cells

Toshiaki Mitsui, Tadeusz Loboda, Ikuko Kamimura, Hidetaka Hori, Kimiko Itoh and Shin-ichiro Mitsunaga

in Plant and Cell Physiology

Published on behalf of Japanese Society of Plant Physiologists

Volume 40, issue 8, pages 773-783
Published in print January 1999 | ISSN: 0032-0781
Published online January 1999 | e-ISSN: 1471-9053 | DOI:
Sucrose-Controlled Transport and Turnover of α-Amylase in Rice (Oryza sativa L.) Cells

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


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We studied the sucrose-controlled intracellular transport and turnover of α-amylase molecules in suspension-cultured cells of rice (Oryza sativa L.) employing pulse labeling techniques with [35S] amino acids. The secretion of two classes of α-amylase isoforms, α-amylase I-1 (encoded by RAmy1A) and II-4 (encoded by RAmy3D) was differentially controlled by sucrose. In rice cells labeled with [35S] amino acids under different sucrose-supplemented conditions, sucrose preferentially prevented the extracellular liberation of [35S]-labeled α-amylase II-4 molecules from rice cells at around 2 mM, whereas the de novo protein synthesis still occurred at this concentration. Pulse-chase experiments showed that sucrose regulates the intracellular transport of [35S]α-amylase II-4 molecules and stimulates the protein turnover. However, cycloheximide, a protein synthesis inhibitor, was induced the extracellular liberation and reduced the turnover of [35S]α-amylase II-4 molecules in the presence of sucrose. These results strongly suggested that newly synthesized sucrose-induced proteins are involved in the posttranslational regulation on sucrose-controlled α-amylase secretion in rice cells.

Keywords: α-Amylase isoform; Intracellular transport; Protein turnover; Rice cells; Secretory protein; Sucrose

Journal Article.  0 words. 

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

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