Transgenic Analysis of the Leishmania MAP Kinase MPK10 Reveals an Auto-inhibitory Mechanism Crucial for Stage-Regulated Activity and Parasite Viability

• DOI: 10.1371/journal.ppat.1004347
• Publication Date: 2014-09-18T18:26:08Z
• Authors: Mathieu Cayla; Najma Rachidi; Olivier Leclercq; Dirk Schmidt-Arras; Heidi Rosenqvist; Martin Wiese; Gerald F. Späth
• Keywords: Amastigote

Protozoan pathogens of the genus Leishmania have evolved unique signaling mechanisms that can sense changes in host environment and trigger adaptive stage differentiation essential for cell infection. The underlying parasite development remain largely elusive even though mitogen-activated protein kinases (MAPKs) been linked previously to environmentally induced virulence. Here, we unravel highly unusual regulatory MAP kinase 10 (MPK10). Using a transgenic approach, demonstrate MPK10 is stage-specifically regulated, as its activity increases during promastigote amastigote conversion. However, unlike canonical MAPKs are activated by dual phosphorylation TxY motif activation loop, independent from tyrosine residue, which constitutive. Removal last 46 amino acids resulted significantly enhanced both recombinant protein, revealing regulated an auto-inhibitory mechanism. Over-expression this hyperactive mutant parasites led dominant negative effect causing massive death differentiation, demonstrating nature auto-inhibition viability. Moreover, phosphoproteomics analyses identified novel phospho-serine residue C-terminal domain at position 395 could be implicated regulation. Finally, uncovered feedback loop limits through dephosphorylation motif. Together our data reveal aspects regulation Leishmania, propose potential signal sensor mammalian environment, whose intrinsic pre-activated conformation auto-inhibition.