Phosphorylation control of protein tyrosine phosphatase A activity in Mycobacterium tuberculosis

Abstract

Edited by Zhijie Chang Keywords:Protein tyrosine kinase A Protein tyrosine phosphatase A Protein kinase A Phosphorylation Mycobacterium tuberculosis a b s t r a c t Protein tyrosine phosphatase A (PtpA) has been shown to play a key role in human macrophage infection by Mycobacterium tuberculosis (Mtb). Protein tyrosine kinase A (PtkA) was the first protein tyrosine kinase shown to phosphorylate PtpA. Here, we found that PtkA-mediated phosphorylation of PtPA on Tyr-128 and Tyr-129 enhances the PtPA phosphatase activity. Moreover, ex-vivo proteinprotein interaction assays showed that PtpA can be phosphorylated by several eukaryotic-like Ser/ Thr protein kinases, such as protein kinase A (PknA). PknA was found to regulate PtpA phosphatase activity through Thr-45 phosphorylation. These results indicate that members of two independent families of protein kinases tune PtpA activity in Mtb.

Phosphorylation of Mycobacterium tuberculosis protein tyrosine kinase A PtkA by Ser/Thr protein kinases

“…PtpA also represses host apoptosis by dephosphorylating GSK3a (Glycogen Synthase Kinase 3a) [29] and potentially macrophage's bioenergetics state [30]. Our most recent study showed that PtkA positively regulates PtpA phosphatase activity [31]. Taken together, this set of evidence suggests a potential role for PtkA in the control of PtpA and related pathophysiological events in Mtb.…”

“…In this study, we show that PknD and PknK phosphorylate PtkA and enhance its autophosphorylation activity in vitro. More interestingly, our recent work has shown that PtkA and PknA enhance PtpA phosphatase activity through phosphorylation of tyrosines and threonine residues on PtpA [31]. However, PknA does not effect PtkA phosphorylation, suggesting that phosphorylation might effect other aspects like substrate specificity or affinity.…”

“…The expression of kinase domains of PknA, PknB, PknD, PknE, PknF, PknI, PknJ, PknK, and PknL from Mtb were performed as described before [31].…”

“…The mycobacterial protein fragment complementation assay was performed as described [31,39]. The genes of interest were PCR-amplified and cloned into pUAB100 (expressing mDHFR fragment F1, 2) or pUAB200 (expressing mDHFR fragment F3).…”

Systematic Analysis of Mycobacterial Acylation Reveals First Example of Acylation-mediated Regulation of Enzyme Activity of a Bacterial Phosphatase

“…PtpB subverts the innate immune signaling by blocking ERK1/2 and p38-mediated pathways (70). PtpA has been previously shown to be regulated by PTMs such as S-nitrosylation (92) and phosphorylation (93,94), but no modifications were known to occur on PtpB. This is the first study that depicts the regulation of M. tuberculosis PtpB enzyme activity by any PTM.…”