Antisera raised to an MBP-Pf41 fusion protein (Pf41 amino acids 115–229) recognize a protein of 40 kDa in P. falciparum (3D7) parasites that were either saponin-lysed (S) or untreated (NS) prior to solubilization in non-reducing sample buffer. The reactivity of mouse anti-Pf41 antibodies with schizonts and free merozoites in a double labeling immunofluorescence assay with rabbit anti-MSP1 antibodies is shown. The arrows indicate the apical end of the parasite (dense structure).Sanders PR, Gilson PR, Cantin GT, Greenbaum DC, Nebl T, Carucci DJ, McConville MJ, Schofield L, Hodder AN, Yates JR 3rd, Crabb BS. Distinct protein classes including novel merozoite surface antigens in Raft-like membranes of Plasmodium falciparum. J Biol Chem. 2005 280:40169-76.

The genes for P12 and P41 can be disrupted and are therefore not essential for parasite growth. Immunofluorescence microscopy of Dp12 and Dp41 and parental 3D7 parasites probed with rabbit anti-P12 and anti-P41 IgGs in addition to the merozoite surface marker MSP1 mAb indicate absence of protein expression in the mutants aside from minor cross-reactivity.Taechalertpaisarn T, Crosnier C, Bartholdson SJ, Hodder AN, Thompson J, Bustamante LY, Wilson DW, Sanders PR, Wright GJ, Rayner JC, Cowman AF, Gilson PR, Crabb BS. Biochemical and Functional Analysis of Two Plasmodium falciparum Blood-Stage 6-Cys Proteins: P12 and P41. PLoS One. 2012;7(7):e41937.

Expression and co-localization of proteins of Pfs38 complex on Plasmodium merozoites. Co-localization studies were performed by immunofluorescence assays. Merozoites were labelled with (a) mouse anti-Pfs38 and rabbit anti-GLURP or with (b) mouse anti-Pfs38 and rabbit anti-Pfs41 antibodies or with (c) mouse anti-Pfs38 and rabbit anti-Pfs12 antibodies or with (d) mouse anti-Pfs38 and rabbit anti-PfsMSP165 antibodies. Partial co-localization was observed between Pfs38 and other proteins of 6-Cys complex with co-localization coefficient of 0.75, 0.61, 0.82, and 0.83 for a–d, respectively. Td represent bright field images. Pfs38 partially co-localized with GLURP, Pfs41, Pfs12, and MSP-1, advocating the co-existence of proteins of 6-Cys protein complex on the merozoite surface (Fig. 3a–d). These results were corroborated by cosedimentation analysis of parasite-derived polypeptides. Western blotting and LC–MS/MS analysis of the glycerol gradient fractions revealed the presence of Pfs38, Pfs41, Pfs12, GLURP, MSP-1, and SERA5 in a single fraction, suggesting that these proteins exist in a complex on the parasite.Paul G, Deshmukh A, Kaur I, Rathore S, Dabral S, Panda A, Singh SK, Mohmmed A, Theisen M, Malhotra P. A novel Pfs38 protein complex on the surface of Plasmodium falciparum blood-stage merozoites. Malar J. 2017 16(1):79