Mutant/mutation
The mutant expresses a C-terminal GFP-tagged version of MAPK1 (mitogen-activated protein kinase 1)

Protein (function)
MAP kinases are serine/threonine protein kinases involved in a variety of functions including cell proliferation. In Plasmodium two MAPK proteins have been identified, MAPK1 (MAP1) and MAPK2 (MAP2).
Using reverse genetics approaches MAPK1 was shown to be dispensable during blood and mosquito stage development in both P. falciparum and P. berghei  (RMgm-526). While MAPK2 was found to be dispensable in asexual blood stages but essential for male gametogenesis in P. berghei , a vital function of this kinase in  asexual blood stage parasites was demonstrated in P. falciparum.

Phenotype
Analyses of a mutant lacking expression of MAPK1 (see RMgm-526) indicate a non-essential role of MAPK1 during the complete life cycle.

Analyses of the Pb_endPbMAPK1-GFP mutant revealed a nuclear localization of  PbMAPK1 in the early schizont stage. 
Through analysis of additional mutants expressing mutated forms of MAPK1 evidence is presented for a nuclear location mediated by nuclear localization signals in the C-terminal domain (see Additional information).

Additional information
Several additional mutants were generated that express (episomally) MAPK1-GFP under different (stronger) promoters (including mutated forms of MAPK1). The use of these mutants revealed a dynamic, stage-specific localization of the respective fusion protein. While the PbMAPK1 protein was found to be enriched in the parasite nuclei at the early schizont stage a uniform cytosolic localization was observed at late schizont stages. This rapidly changed during the cytomere stage to transient, commashaped structures that did not co-localize with parasite nuclei and then back to a uniform cytosolic distribution in mature merozoites. Localisation was independent of C- or N-terminal tagging of MAPk1 with GFP.

Primary structure analysis of MAPK1 in different rodent malaria species revealed four sequence segments with putative NLS (nuclear localization signal) function, two of them residing in the catalytic and the C-terminal domain, respectively.
To test the functionality of these putative NLSs, HepG2 cells infected with transgenic parasites expressing GFP fused to either the catalytic domain (PbMAPK1-catD(D178A)-GFP) or to the C-terminal domain (GFPPbMAPK1-CTD) of PbMAPK1 were analyzed 30 hpi by confocal live cell imaging. While the 68 kDa PbMAPK1-catD(D178A)-GFP fusion protein was found in the parasite cytosol excluded from the parasite nuclei, the GFP-PbMAPK1-CTD fusion protein showed a clear nuclear localization

Other mutants
A mutant lacking expression of MAPK1 (see RMgm-526)