Different sensitivity to wortmannin of two vacuolar sorting signals indicates the presence of distinct sorting machineries in tobacco cells.
Different sensitivity to wortmannin of two vacuolar sorting signals indicates the presence of distinct sorting machineries in tobacco cells.
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DOI：
10.1083/jcb.130.6.1307
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发表时间：
1995-09
影响因子：
7.8
通讯作者：
NAKAMURA, K
中科院分区：
文献类型：
--
作者：
MATSUOKA, K;BASSHAM, DC;RAIKHEL, NV;NAKAMURA, K
植物细胞中的核仁基质蛋白从分泌途径被分选到高尔基体的液泡中。在此之前，我们报道了孢子素前体的NH 2-末端前肽（NTPP）和大麦凝集素前体的COOH-末端前肽（CTPP）含有液泡分选的信息。为了分析这些前肽是否是可互换的，我们在烟草BY-2细胞中表达了由野生型或突变的NTPP与大麦凝集素的成熟部分和孢子素与CTPP和突变的NTPP组成的构建体。这些构建体的液泡定位表明信号是可互换的。接下来，我们分析了渥曼青霉素，一种哺乳动物磷脂酰肌醇（PI）3-激酶的特异性抑制剂，对烟草细胞中NTPP和CTPP空泡递送的影响。脉冲追踪分析表明，33 μ M渥曼青霉素引起几乎完全抑制CTPP介导的运输到液泡，而NTPP介导的运输显示几乎没有敏感性渥曼青霉素在这个浓度。这表明烟草细胞中至少存在两种不同的液泡分选机制，并且CTPP介导的途径对渥曼青霉素敏感。我们比较了渥曼青霉素对CTPP介导的蛋白质空泡递送的抑制和对烟草细胞中磷脂合成的抑制的剂量依赖性。Wortmannin抑制PI 3-和PI 4-激酶活性和磷脂合成。渥曼青霉素引起的错配显示出与抑制PI 4-磷酸和主要磷脂合成的剂量依赖性相似的剂量依赖性。然而，这与PI 3-磷酸合成的抑制不同。因此，磷脂的合成可能参与CTPP介导的液泡运输。
Vacuolar matrix proteins in plant cells are sorted from the secretory pathway to the vacuoles at the Golgi apparatus. Previously, we reported that the NH2-terminal propeptide (NTPP) of the sporamin precursor and the COOH-terminal propeptide (CTPP) of the barley lectin precursor contain information for vacuolar sorting. To analyze whether these propeptides are interchangeable, we expressed constructs consisting of wild-type or mutated NTPP with the mature part of barley lectin and sporamin with CTPP and mutated NTPP in tobacco BY-2 cells. The vacuolar localization of these constructs indicated that the signals were interchangeable. We next analyzed the effect of wortmannin, a specific inhibitor of mammalian phosphatidylinositol (PI) 3-kinase on vacuolar delivery by NTPP and CTPP in tobacco cells. Pulse-chase analysis indicated that 33 microM wortmannin caused almost complete inhibition of CTPP-mediated transport to the vacuoles, while NTPP-mediated transport displayed almost no sensitivity to wortmannin at this concentration. This indicates that there are at least two different mechanisms for vacuolar sorting in tobacco cells, and the CTPP-mediated pathway is sensitive to wortmannin. We compared the dose dependencies of wortmannin on the inhibition of CTPP-mediated vacuolar delivery of proteins and on the inhibition of the synthesis of phospholipids in tobacco cells. Wortmannin inhibited PI 3- and PI 4-kinase activities and phospholipid synthesis. Missorting caused by wortmannin displays a dose dependency that is similar to the dose dependency for the inhibition of synthesis of PI 4-phosphate and major phospholipids. This is different, however, than the inhibition of synthesis of PI 3- phosphate. Thus, the synthesis of phospholipids could be involved in CTPP-mediated vacuolar transport.
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影响因子：
11.6
作者：
GOMEZ, L;CHRISPEELS, MJ
通讯作者：
CHRISPEELS, MJ
影响因子：
11.6
作者：
HOLWERDA, BC;PADGETT, HS;ROGERS, JC
通讯作者：
ROGERS, JC
DOI：
10.1073/pnas.91.20.9617
发表时间：
1994-09-27
影响因子：
11.1
作者：
HONG, ZG;VERMA, DPS
通讯作者：
VERMA, DPS
影响因子：
11.4
作者：
KOTANI, K;YONEZAWA, K;KASUGA, M
通讯作者：
KASUGA, M
DOI：
10.1073/pnas.91.8.3403
发表时间：
1994-04-12
影响因子：
11.1
作者：
KIRSCH, T;PARIS, N;ROGERS, JC
通讯作者：
ROGERS, JC