Immunofluorescence studies performed on blood smears made from cultures containing parasites of different stages using antisera against PfSRPK1 (red), PfSR1 (green). Parasite nuclei were stained with DAPI. The staining for PfSR1 and PfSRPK1 overlapped in all parasitic stages These proteins were present predominantly inside the nucleus in the ring stages as indicated by co-localization with nuclear dye DAPI. PfSRPK1 and PfSR1 were present in the nucleus of ~75% of rings and young trophozoites that were analyzed. As the parasites matured, PfSRPK1 and PfSR1 seemed to be exported to nuclear periphery and/or cytoplasm in mature trophozoites. Both these proteins were predominantly in the cytoplasm of most (>80%) schizonts.Dixit A, Singh PK, Sharma GP, Malhotra P, Sharma P. PfSRPK1, a novel splicing-related kinase from Plasmodium falciparum. J Biol Chem. 2010 285(49):38315-23

Immunofluorescence assays, using specific antibodies, detected the proteins of interest (in green) in asexual blood stage (ABS) parasites, using MSP1 (in red). Nuclei were highlighted by Hoechst nuclear stain (in blue). Bar, 5 μm. Ngwa CJ, Scheuermayer M, Mair GR, Kern S, Brügl T, Wirth CC, Aminake MN, Wiesner J, Fischer R, Vilcinskas A, Pradel G. Changes in the transcriptome of the malaria parasite Plasmodium falciparum during the initial phase of transmission from the human to the mosquito. BMC Genomics. 2013 Apr 15;14:256

Subcellular localization of PfCLK-3 and PfCLK-4 in the blood stage. Mixed asexual blood stage cultures containing trophozoites (TZ) and schizonts (SZ) cultures were fixed with methanol and prepared for IFA, using rat antisera against PfCLK-3 and mouse antisera against PfCLK-4 (green). The parasite nuclei were highlighted by Hoechst staining (blue). The asexual blood stages were labelled with rabbit antisera against PfMSP-1. Bar, 5 mm. PfCLK-3 and PfCLK-4 are mainly present in the nucleus of trophozoites, while in schizonts and gametocytes both kinases are primarily located in the cytoplasm. Particularly for PfCLK-3 a rim-associated labelling pattern was observed in the latter stages. In the IFAs, the asexual blood stage parasites were highlighted by labelling of plasmalemma-associated proteins, i.e. PfMSP-1.Kern S, Agarwal S, Huber K, Gehring AP, Strödke B, Wirth CC, Brügl T, Abodo LO, Dandekar T, Doerig C, Fischer R, Tobin AB, Alam MM, Bracher F, Pradel G. Inhibition of the SR Protein-Phosphorylating CLK Kinases of Plasmodium falciparum Impairs Blood Stage Replication and Malaria Transmission. PLoS One. 2014 Sep 4;9(9):e105732.

Co-localization and control IFAs. A. Immunolabelling of PfCLK-1 with rabbit antisera (red) detected the kinase in the schizonts´ cytoplasm as well as in the nuclei, where it co-localizes with the three SR proteins (green). Schizonts were counterlabelled with rabbit antibodies against PfMSP-1 (red). All nuclei were highlighted by Hoechst staining (blue). Bar, 5 μm. The co-localization experiments confirmed that the SR proteins are solely present in the nuclei, while in the early schizont stage, PfCLK-1 is present both in the parasite nuclei and the cytoplasm. Co-localization of PfCLK-1 with the three SR proteins can be detected in distinct nuclear regions. Kern S, Agarwal S, Huber K, Gehring AP, Strödke B, Wirth CC, Brügl T, Abodo LO, Dandekar T, Doerig C, Fischer R, Tobin AB, Alam MM, Bracher F, Pradel G. Inhibition of the SR Protein-Phosphorylating CLK Kinases of Plasmodium falciparum Impairs Blood Stage Replication and Malaria Transmission. PLoS One. 2014 Sep 4;9(9):e105732.