Free ricin a chain, proricin, and native toxin have different cellular fates when expressed in tobacco protoplasts

被引:74
作者
Frigerio, L
Vitale, A
Lord, JM
Ceriotti, A
Roberts, LM
机构
[1] CNR, Inst Biosintesi Vegetali, I-20133 Milan, Italy
[2] Univ Warwick, Dept Biol Sci, Coventry CV4 7AL, W Midlands, England
关键词
D O I
10.1074/jbc.273.23.14194
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
The catalytic A subunit of ricin can inactivate eukaryotic ribosomes, including those of Ricinus communis where the toxin is naturally produced. How such plant cells avoid intoxication has remained an open question. Here we report the transient expression of a number of ricin A chain-encoding cDNA constructs ill tobacco protoplasts, Ricin A chain entered the endoplasmic reticulum lumen, where it was efficiently glycosylated, but it was toxic to the cells and disappeared with time in a brefeldin A-insensitive manner, suggesting reverse translocation to the cytosol and eventual degradation. Proricin (the natural precursor form containing A and B chains joined together by a Linker sequence) was glycosylated, transported to the vacuole, and processed to its mature form, but was not toxic, Free ricin A chain and proricin were not secreted, whereas free ricin B chain was found entirely in the extracellular medium. The coexpression of ricin A and B chains resulted in the formation of disulfide-linked, transport-competent heterodimers, which were secreted, with a concomitant reduction in the observed cytotoxicity. These results suggest that the production of ricin as a precursor is essential for its routing to the vacuole and for protection of ricin-producing cells.
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页码:14194 / 14199
页数:6
相关论文
共 35 条
  • [1] FILM DETECTION METHOD FOR TRITIUM-LABELED PROTEINS AND NUCLEIC-ACIDS IN POLYACRYLAMIDE GELS
    BONNER, WM
    LASKEY, RA
    [J]. EUROPEAN JOURNAL OF BIOCHEMISTRY, 1974, 46 (01): : 83 - 88
  • [2] RICIN AND RICINUS-COMMUNIS AGGLUTININ SUBUNITS ARE ALL DERIVED FROM A SINGLE-SIZE POLYPEPTIDE PRECURSOR
    BUTTERWORTH, AG
    LORD, JM
    [J]. EUROPEAN JOURNAL OF BIOCHEMISTRY, 1983, 137 (1-2): : 57 - 65
  • [3] EXPRESSION OF THE WILD-TYPE AND MUTATED VACUOLAR STORAGE PROTEIN PHASEOLIN IN XENOPUS OOCYTES REVEALS RELATIONSHIPS BETWEEN ASSEMBLY AND INTRACELLULAR-TRANSPORT
    CERIOTTI, A
    PEDRAZZINI, E
    FABBRINI, MS
    ZOPPE, M
    BOLLINI, R
    VITALE, A
    [J]. EUROPEAN JOURNAL OF BIOCHEMISTRY, 1991, 202 (03): : 959 - 968
  • [4] DAMICO L, 1992, PLANT J, V2, P443
  • [5] PEA LECTIN IS CORRECTLY PROCESSED, STABLE AND ACTIVE IN LEAVES OF TRANSGENIC POTATO PLANTS
    EDWARDS, GA
    HEPHER, A
    CLERK, SP
    BOULTER, D
    [J]. PLANT MOLECULAR BIOLOGY, 1991, 17 (01) : 89 - 100
  • [6] ENDO Y, 1988, J BIOL CHEM, V263, P8735
  • [7] INHIBITION OF PROTEASOME ACTIVITIES AND SUBUNIT-SPECIFIC AMINO-TERMINAL THREONINE MODIFICATION BY LACTACYSTIN
    FENTEANY, G
    STANDAERT, RF
    LANE, WS
    CHOI, S
    COREY, EJ
    SCHREIBER, SL
    [J]. SCIENCE, 1995, 268 (5211) : 726 - 731
  • [8] GOMEZ L, 1993, PLANT CELL, V5, P1113, DOI 10.1105/tpc.5.9.1113
  • [9] The C-terminal HDEL sequence is sufficient for retention of secretory proteins in the endoplasmic reticulum (ER) but promotes vacuolar targeting of proteins that escape the ER
    Gomord, V
    Denmat, LA
    FitchetteLaine, AC
    SatiatJeunemaitre, B
    Hawes, C
    Faye, L
    [J]. PLANT JOURNAL, 1997, 11 (02) : 313 - 325
  • [10] GENOMIC CLONING AND CHARACTERIZATION OF A RICIN GENE FROM RICINUS-COMMUNIS
    HALLING, KC
    HALLING, AC
    MURRAY, EE
    LADIN, BF
    HOUSTON, LL
    WEAVER, RF
    [J]. NUCLEIC ACIDS RESEARCH, 1985, 13 (22) : 8019 - 8033