SURFIN4.2 localizes at the rhoptry neck. (A) Whole merozoites where the electrodense club-shaped rhoptries are clearly observed. (B) Image enlargements of the corresponding pictures shown in A. showing the rhoptries in more detail, SURFIN4.2 is clearly present in the most terminal part of the organelle: the neck. Scale bar represent 200nm. iEM was chosen as an approach to determine the SURFIN4.2 subcellular localization, due to the clear and easy morphological identification of the rhoptries in EM. SURFIN4.2 was clearly observed at the more apical end of the rhoptries, the neck, consistent with the apical pattern observed by IFA. Interestingly, RON4 is also localized in the neck of the rhoptries, supporting the interaction hereby described with SURFIN4.2.
Quintana MDP, Ch'ng JH, Zandian A, Imam M, Hultenby K, Theisen M, Nilsson P, Qundos U, Moll K, Chan S, Wahlgren M. SURGE complex of Plasmodium falciparum in the rhoptry-neck (SURFIN4.2-RON4-GLURP) contributes to merozoite invasion. PLoS One. 2018 Aug 9;13(8):e0201669.