The N-terminal propeptide of the precursor to sporamin acts as a vacuole-targeting signal even at the C terminus of the mature part in tobacco cells

Yasuhiro Koide, Hideyuki Hirano, Ken Matsuoka, Kenzo Nakamura

Research output: Contribution to journalArticle

34 Citations (Scopus)

Abstract

An asparagine-proline-isoleucine-arginine-leucine (NPIRL) and its related sequences in the N-terminal propeptides (NTPP) of several plant vacuolar proteins, including that of sporamin from sweet potato (SPO) function as vacuole-targeting determinants in a manner that is distinct from the vacuole-targeting determinant in the CTPPs of other plant vacuolar proteins. When the mutant precursor to sporamin, SPO-NTPP (in which NTPP was moved to the C terminus of the mature part), was expressed in tobacco (Nicotiana tabacum) cells, the pro-form was efficiently targeted to the vacuole and the NTPP was cleaved off. Unlike the results obtained with the wild-type precursor, substitution of the NPIRL sequence in the C-terminally located NTPP to asparagine-proline-glycine-arginine-leucine in the SPO-isoleucine-28-to-glycine mutant resulted in missorting of less than 20% of the pro-form to the medium. Unlike the vacuolar transport of SPO-NTPP, the vacuolar transport of SPO-isoleucine-28-to-glycine was strongly inhibited by 33 μM wortmannin, which is similar to the C-terminal propeptide-mediated vacuolar transport. These results suggest that the vacuole-targeting function of the NPIRL sequence is not strictly dependent on its location at the N terminus of a protein and that the C-terminally located mutant NTPP acquired some physicochemical properties of the C-terminal vacuole-targeting sequence.

Original languageEnglish
Pages (from-to)863-870
Number of pages8
JournalPlant physiology
Volume114
Issue number3
DOIs
Publication statusPublished - 1997

All Science Journal Classification (ASJC) codes

  • Physiology
  • Genetics
  • Plant Science

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