Müntz Klaus
Institut für Pflanzengenetik und Kulturpflanzenforschung (IPK), Corrensstr 3, D-06466, Gatersleben, Germany.
J Exp Bot. 2007;58(10):2391-407. doi: 10.1093/jxb/erm089. Epub 2007 Jun 1.
Plant cells cannot live without their vacuoles. The tissues and organs of a plant contain a wide variety of differentiated and specialized vacuoles -- even a single plant cell can possess two or more types of vacuoles. Vacuolar proteins are encoded by nuclear genes and synthesized in the cytoplasm. Their transport into the vacuolar compartment is under cytoplasmic control. Transcription seems to be a major control level for differential protein supply to the vacuoles. It is at this level that vacuole differentiation and functions are mainly integrated into cellular processes. Recycling amino acids generated by protein degradation is a major function of the vacuole. This is most evident when storage proteins are mobilized in storage tissues of generative or vegetative organs in order to nourish the embryo of germinating seeds or sprouting buds. When specific proteins are transferred to the vacuole for immediate degradation this compartment contributes to the adaptation of protein complexes in response to changes in developmental or environmental conditions. Vacuolar proteases are involved in protein degradation during reversible senescence and programmed cell death, which is also called irreversible senescence. Vacuoles contribute to defence against pathogens and herbivores by limited and unlimited proteolysis. Our present knowledge on functions and processes of vacuolar protein dynamics in plants is reviewed. Research perspectives are deduced.
植物细胞没有液泡就无法存活。植物的组织和器官包含各种各样分化和特化的液泡——甚至单个植物细胞都可能拥有两种或更多类型的液泡。液泡蛋白由核基因编码并在细胞质中合成。它们向液泡区室的运输受细胞质控制。转录似乎是向液泡供应差异蛋白的主要控制水平。正是在这个水平上，液泡的分化和功能主要整合到细胞过程中。回收蛋白质降解产生的氨基酸是液泡的一项主要功能。当储存蛋白在生殖或营养器官的储存组织中被调动起来以滋养萌发种子的胚或发芽的芽时，这一点最为明显。当特定蛋白质被转移到液泡中立即降解时，这个区室有助于蛋白质复合物适应发育或环境条件的变化。液泡蛋白酶参与可逆衰老和程序性细胞死亡（也称为不可逆衰老）过程中的蛋白质降解。液泡通过有限和无限的蛋白水解作用来抵御病原体和食草动物。本文综述了我们目前对植物液泡蛋白动态功能和过程的认识，并推断了研究前景。
