Purification and characterization of serine proteases that exhibit caspase-like activity and are associated with programmed cell death in Avena sativa
Purification and characterization of serine proteases that exhibit caspase-like activity and are associated with programmed cell death in Avena sativa
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DOI：
10.1105/tpc.017947
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发表时间：
2004-04-01
期刊：
影响因子：
11.6
通讯作者：
Wolpert, TJ
中科院分区：
文献类型：
--
作者：
Coffeen, WC;Wolpert, TJ
燕麦维多利亚疫病是由维氏柯氏杆菌(Cochliobolus Victoriae)引起的，由于维克托林毒素的产生而致病。在敏感的紫花苜蓿中，Victorin诱导的反应被描述为一种程序性细胞死亡(PCD)的形式，并表现出类似于细胞凋亡的形态和生化特征，包括染色质凝聚、DNA梯形、细胞收缩、线粒体功能改变和有序的底物特异性蛋白分解事件。维克托林诱导的核酮糖-1，5-二磷酸羧基酶/加氧酶(Rubisco)的蛋白分解被caspase特异性和一般的蛋白酶抑制剂所阻止。有证据表明，导致Rubisco蛋白分解的信号级联反应涉及多种蛋白酶。此外，还对两种明显参与Rubisco蛋白水解级联反应的蛋白水解酶进行了纯化和鉴定。这些酶表现出caspase专一性，并显示与植物枯草杆菌素样丝氨酸蛋白酶同源的氨基酸序列。这些蛋白水解酶是以活性形式存在的，在维托林或热休克诱导PCD后重新定位到细胞外液中。这些酶作为过程性蛋白水解酶参与了PCD反应过程中的信号级联反应。
Victoria blight of Avena sativa (oat) is caused by the fungus Cochliobolus victoriae, which is pathogenic because of the production of the toxin victorin. The victorin-induced response in sensitive A. sativa has been characterized as a form of programmed cell death (PCD) and displays morphological and biochemical features similar to apoptosis, including chromatin condensation, DNA laddering, cell shrinkage, altered mitochondrial function, and ordered, substrate-specific proteolytic events. Victorin-induced proteolysis of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) is shown to be prevented by caspase-specific and general protease inhibitors. Evidence is presented for a signaling cascade leading to Rubisco proteolysis that involves multiple proteases. Furthermore, two proteases that are apparently involved in the Rubisco proteolytic cascade were purified and characterized. These proteases exhibit caspase specificity and display amino acid sequences homologous to plant subtilisin-like Ser proteases. The proteases are constitutively present in an active form and are relocalized to the extracellular fluid after induction of PCD by either victorin or heat shock. The role of the enzymes as processive proteases involved in a signal cascade during the PCD response is discussed.