Department of Biology, 108 Coker Hall, University of North Carolina (UNC), CB 3280, Chapel Hill, NC 27599-3280, USA.
Science. 2010 Dec 3;330(6009):1393-7. doi: 10.1126/science.1194980. Epub 2010 Nov 18.
Metacaspases are distant relatives of animal caspases found in protozoa, fungi, and plants. Limited experimental data exist defining their function(s), despite their discovery by homology modeling a decade ago. We demonstrated that two type I metacaspases, AtMC1 and AtMC2, antagonistically control programmed cell death in Arabidopsis. AtMC1 is a positive regulator of cell death and requires conserved caspase-like putative catalytic residues for its function. AtMC2 negatively regulates cell death. This function is independent of the putative catalytic residues. Manipulation of the Arabidopsis type I metacaspase regulatory module can nearly eliminate the hypersensitive cell death response (HR) activated by plant intracellular immune receptors. This does not lead to enhanced pathogen proliferation, decoupling HR from restriction of pathogen growth.
类半胱天冬酶是在原生动物、真菌和植物中发现的动物半胱天冬酶的远亲。尽管十年前通过同源建模发现了它们，但关于它们的功能的实验数据有限。我们证明，两种 I 型类半胱天冬酶 AtMC1 和 AtMC2 拮抗地控制拟南芥中的程序性细胞死亡。AtMC1 是细胞死亡的正调节剂，其功能需要保守的半胱天冬酶样假定催化残基。AtMC2 负调节细胞死亡。该功能与假定的催化残基无关。对拟南芥 I 型类半胱天冬酶调节模块的操作几乎可以消除植物细胞内免疫受体激活的超敏性细胞死亡反应 (HR)。这不会导致病原体增殖增加，将 HR 与限制病原体生长解耦。
