Phosphoinositide Metabolism Links cGMP-Dependent Protein Kinase G to Essential Ca2+ Signals at Key Decision Points in the Life Cycle of Malaria Parasites
Figure 5
PKG controls cytosolic Ca2+ levels in ookinete and upon gametocyte activation in P. berghei.
(A and B) Determination of relative cytosolic Ca2+ levels in purified ookinetes expressing PKG-HA or PKGT619Q-HA using pericam, a dual excitation Ca2+ reporter. We added 0.5 µM C2 treatment (A) or DMSO treatment (B) at t = 20 s. Fluorescence was normalised as follows: ΔF = (Fn−F20)/F20, in which Fn is the fluorescence at t = n s; F20 is the reference time before addition of C2 or DMSO, and was normalised to the baseline provided by the C2-resistant parasites expressing PKGT619Q-HA. Error bars show standard errors from three independent replicates each using 10 ookinetes per condition. See Figure S6A and Figure S6B for a validation of the pericam reporter in P. berghei. (C) Luminescence responses of gametocytes expressing GFP-aequorin to different concentrations of C2. Gametocytes were stimulated with 50 µM XA at t = 0 s. Data are representative of at least four independent experiments.