Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, School of Life Sciences, Southwest University, Beibei, Chongqing 400715, China.
J Cell Biochem. 2012 Apr;113(4):1087-95. doi: 10.1002/jcb.23449.
Mycobacterium tuberculosis is the most successful pathogen with multiple mechanisms to subvert host immune response, resulting in insidious disease. A unique Mycobacterium antigen family termed PPE (Pro-Pro-Glu) has long been widely speculated as "molecular mantra" to escape host immunity. Members of this family are characterized by a conserved N terminal and a variable C terminal. This family associated closely with ESAT-6(ESX) secretion system and largely located in cell wall or cell membrane. The expression of PPE protein is temporally regulated, and highly expressed during M. tuberculosis persistence. Importantly, the distribution of PPE family is so far limited to Mycobacterium genus, prevalent among pathogenic Mycobacterium species. It is tempting to explore this family due to its potential in the latency and reactivation of M. tuberculosis. The evolution, structure, and functions of most PPE proteins remain elusive. The understanding of these questions will deepen our appreciation of the pathogenesis of M. tuberculosis and accelerate novel anti-TB measures discovery.
结核分枝杆菌是最成功的病原体之一，具有多种机制来颠覆宿主免疫反应，导致隐匿性疾病。一个独特的分枝杆菌抗原家族，称为 PPE（脯氨酸-脯氨酸-谷氨酸），长期以来被广泛推测为“分子咒语”，以逃避宿主免疫。该家族的成员具有保守的 N 端和可变的 C 端。这个家族与 ESAT-6(ESX)分泌系统密切相关，主要位于细胞壁或细胞膜中。PPE 蛋白的表达是时间调控的，在结核分枝杆菌持续存在期间高度表达。重要的是，PPE 家族的分布迄今为止仅限于分枝杆菌属，在致病性分枝杆菌物种中很常见。由于其在结核分枝杆菌潜伏和再激活中的潜在作用，探索这个家族是很有吸引力的。大多数 PPE 蛋白的进化、结构和功能仍然难以捉摸。对这些问题的理解将加深我们对结核分枝杆菌发病机制的认识，并加速新的抗结核措施的发现。
