Global discovery the PstP interactions using Mtb proteome microarray and revealing novel connections with EthR.

Mycobacterium tuberculosis (Mtb) serine/threonine protein phosphatase PstP plays an important role in regulating Mtb cell division and growth by reversible phosphorylation signaling. However, the substrates of Mtb with which the PstP interacts, and the underlying molecular mechanisms are still largely unknown. In this study, we performed an Mtb proteome microarray to globally identify the PstP bindings. In this way, we discovered 78 interactors between PstP and Mtb proteins, and found a novel connections with EthR. The interaction between PstP and EthR has been validated by Bio-Layer interferometry and Yeast-two-hybrid. And functional studies showed that PstP significantly enhances the binding between EthR and related DNA domain through its interaction with EthR. Phenotypically, overexpression of PstP promoted the resistance of Mycobacterium smegmatis with the antibiotic of ethionamide. Overall, we hopefully wish that the PstP interactors identified in this study will serve as a useful resource for further systematic studies of the roles that PstP plays in the regulation of Mtb dephosphorylation. SIGNIFICANCE: Mycobacterium tuberculosis (Mtb) is the causative agent of tuberculosis, which is responsible of ~1.5 million death per year. Understanding the knowledge about the basic biological regulation pathways in Mtb is an effective approach to discover the novel drug targets for cure TB. PstP is a serine/threonine protein phosphatase in Mtb, and plays important roles in regulating Mtb cell division and growth by reversible phosphorylation signaling. In this study, we identified 78 PstP interacting Mtb proteins using Mtb proteome microarray, which could preliminarily explain the roles of PstP played in Mtb. Moreover, functional analysis showed that a novel transcription factor EthR had been found regulated by PstP through binding, which could enhance the resistance to the antibiotic ETH. Overall, this network constructed with PstP-Mtb proteins could serve as a valuable resource for studying Mtb growth.