Department of Molecular Medicine, University of Padova, Padua, Italy.
Center for Cooperative Research in Biosciences (CIC bioGUNE), Basque Research and Technology Alliance (BRTA), Derio, Spain.
J Bacteriol. 2021 Mar 8;203(7). doi: 10.1128/JB.00439-20.
comprises an unusual cell envelope dominated by unique lipids and glycans that provides a permeability barrier against hydrophilic drugs and is central for its survival and virulence. Phosphatidyl--inositol mannosides (PIMs) are glycolipids considered to be not only key structural components of the cell envelope but also the precursors of lipomannan (LM) and lipoarabinomannan (LAM), important lipoglycans implicated in host-pathogen interactions. Here, we focus on PatA, a membrane-associated acyltransferase that transfers a palmitoyl moiety from palmitoyl coenzyme A (palmitoyl-CoA) to the 6-position of the mannose ring linked to the 2-position of inositol in PIM/PIM We validate that the function of PatA is vital for and We constructed a conditional mutant and showed that silencing is bactericidal in batch cultures. This phenotype was associated with significantly reduced levels of AcPIM, an important structural component of the mycobacterial inner membrane. The requirement of PatA for viability was also demonstrated during macrophage infection and in a mouse model of infection, where a dramatic decrease in viable counts was observed upon silencing of the gene. This is reminiscent of the behavior of PimA, the mannosyltransferase that initiates the PIM pathway, also found to be essential for growth and Altogether, the experimental data highlight the significance of the early steps of the PIM biosynthetic pathway for physiology and reveal that PatA is a novel target for drug discovery programs against this major human pathogen. Tuberculosis (TB) is the leading cause of death from a single infectious agent. The emergence of drug resistance in strains of , the etiologic agent of TB, emphasizes the need to identify new targets and antimicrobial agents. The mycobacterial cell envelope is a major factor in this intrinsic drug resistance. Here, we have focused on the biosynthesis of PIMs, key virulence factors and important components of the cell envelope. Specifically, we have determined that PatA, the acyltransferase responsible for the first acylation step of the PIM synthesis pathway, is essential in These results highlight the importance of early steps of the PIM biosynthetic pathway for mycobacterial physiology and the suitability of PatA as a potential new drug target.
包括一种独特的细胞包膜，主要由独特的脂质和聚糖组成，为亲水性药物提供渗透屏障，是其生存和毒力的核心。磷酸酰基肌醇甘露糖苷（PIMs）是糖脂，不仅被认为是细胞包膜的关键结构成分，也是脂甘露聚糖（LM）和脂阿拉伯甘露聚糖（LAM）的前体，这两种重要的糖脂与宿主-病原体相互作用有关。在这里，我们重点介绍 PatA，一种膜相关酰基转移酶，它将棕榈酰部分从棕榈酰辅酶 A（棕榈酰-CoA）转移到与肌醇 2 位相连的甘露糖环的 6 位上的 PIM/PIM 中。我们验证了 PatA 的功能对 和 至关重要。我们构建了一个 条件突变体，并表明在分批培养中沉默 是杀菌的。这种表型与 AcPIM 的水平显著降低有关，AcPIM 是分枝杆菌内膜的重要结构成分。在巨噬细胞感染和感染小鼠模型中也证明了 PatA 对生存的必要性，在沉默 基因后，观察到活菌数明显减少。这让人联想到 PimA 的行为，PimA 是启动 PIM 途径的甘露糖基转移酶，也被发现对 生长至关重要。总之，实验数据强调了 PIM 生物合成途径早期步骤对 生理学的重要性，并揭示了 PatA 是针对这种主要人类病原体的药物发现计划的一个新靶标。结核病（TB）是由单一感染源引起的死亡的主要原因。在结核分枝杆菌（导致结核病的病原体）菌株中出现耐药性，强调了需要确定新的靶点和抗菌剂。分枝杆菌的细胞包膜是这种固有耐药性的一个主要因素。在这里，我们专注于 PIMs 的生物合成，这是一种关键的毒力因子，也是细胞包膜的重要组成部分。具体来说，我们已经确定，负责 PIM 合成途径中第一个酰化步骤的酰基转移酶 PatA，在 中是必不可少的。这些结果强调了 PIM 生物合成途径早期步骤对分枝杆菌生理学的重要性，以及 PatA 作为潜在新药物靶点的适宜性。
