Division of Structural Biology, ICMR-National Institute for Research in Reproductive Health, Mumbai, India.
Genetic Research Center, ICMR-National Institute for Research in Reproductive Health, Mumbai, India.
FEBS Lett. 2020 Oct;594(19):3156-3169. doi: 10.1002/1873-3468.13899. Epub 2020 Aug 30.
Proteolytic processing is an important post-translational modification affecting protein activity and stability. In the current study, we investigate the N-terminal cleavage of Trop2, a protein which is overexpressed in many cancers. We demonstrate that Trop2 is cleaved at Arg87 by a transmembrane serine protease, matriptase. Homology modeling and site-directed mutagenesis of amino acids in close proximity to the matriptase cleavage site reveal the importance of Val194 in regulating Trop2 cleavage. Co-immunoprecipitation studies confirm that amino acid substitutions at Arg87, Thr88, Lys189, Val194, and His195 do not affect Trop2 dimerization. However, cleavage of wild-type Trop2 by matriptase is inhibited when it is allowed to dimerize with a V A mutant monomer, further confirming the role of Val194 in matriptase-mediated N-terminal cleavage.
蛋白水解加工是一种重要的翻译后修饰方式，可影响蛋白质的活性和稳定性。在本研究中，我们研究了 Trop2 的 N 端切割，Trop2 是在许多癌症中过度表达的一种蛋白。我们证明 Trop2 在 Arg87 处被跨膜丝氨酸蛋白酶 matriptase 切割。与 matriptase 切割位点接近的氨基酸的同源建模和定点突变揭示了 Val194 在调节 Trop2 切割中的重要性。共免疫沉淀研究证实，Arg87、Thr88、Lys189、Val194 和 His195 处的氨基酸取代不影响 Trop2 二聚体的形成。然而，当野生型 Trop2 与 V A 突变单体允许二聚化时，matriptase 对其的切割被抑制，这进一步证实了 Val194 在 matriptase 介导的 N 端切割中的作用。
