Lactacystin is a microbial metabolite isolated from Streptomyces that is now widely used as a selective inhibitor of the 20S proteasome.[1],[2],[3] Lactacystin was first characterized by its ability to induce differentiation and inhibit cell cycle progression in several tumor cell lines. At concentrations from 2 to 10 µM, lactacystin induces the outgrowth of neurites in the neuroblastoma cell line Neuro2a.4 Lactacystin irreversibly alkylates subunit X of the 20S proteasome.[3] The concomitant inhibition of proteasome peptidase activity results in the accumulation of a variety of ubiquitinated proteins which would normally undergo rapid degradation. Thus, the effects of lactacystin are pleiotropic and depend substantially on the expression pattern of signalling proteins within the treated cell.
乳酸环素是一种从链霉菌中分离出的微生物代谢产物，现已广泛用作20S蛋白酶体的选择性抑制剂[1],[2],[3]。乳酸环素首先通过其在几种肿瘤细胞系中诱导分化和抑制细胞周期进展的能力而被表征。在2到10微米的浓度下，乳酸环素能够诱导神经母细胞瘤细胞系Neuro2a的神经突起的生长[4]。乳酸环素不可逆地烷基化20S蛋白酶体的X亚基。蛋白酶体肽酶活性的共同抑制导致各种泛素化蛋白的积累，这些蛋白本应快速降解。因此，乳酸环素的效应是多样的，且在所处理的细胞中的信号蛋白的表达模式中具有重要的依赖性。
Reference:
[1]. Omura, S., Fujimoto, T.T., Otoguro, K., et al. Lactacystin, a novel microbial metabolite, induces neuritogenesis of neuroblastoma cells. Journal of Antibiotics 44, 113-116 (1991).
[2]. Corey, E.J., and Reichard, G.A. Total synthesis of lactacystin. Journal of the American Chemical Society 114, 10677-10678 (1992).
[3]. Fenteany, G., and Schreiber, S.L. Lactacystin, proteasome function, and cell fate. The Journal of Biological Chemisty 273(15), 8545-8548 (1998).
[4]. Fenteany, G., Standaert, R.F., Reichard, G.A., et al. A β-lactone related to lactacystin induces neurite outgrowth in a neuroblastoma cell line and inhibits cell cycle progression in an osteosarcoma cell line. Proceedings of the National Academy of Sciences of the United States of America 91, 3358-3362 (1994).