Figure 1.

Genetic knockdown of LITAF increases calcium transients in the heart of zebrafish embryos. Zebrafish hearts from 48 hpf wild-type (WT) and LITAF morphants (MO) were stained with Fura-2 AM to measure Ca²⁺ transients. A, Structure of human and zebrafish LITAF with conserved PXY and P(S/T)AP motifs and the hydrophobic region (HR) required for membrane embedding.²⁵ Also indicated are two conserved cysteine pairs for coordination of a zinc atom likely required for proper protein folding.²⁵ B, Averaged ventricular Ca²⁺ transients (amplitudes and baselines) from regions of interest (ROIs) in panel C. C, Color maps of Ca²⁺ transient amplitudes from wild-type and LITAF morphant hearts. Color code depicts Ca²⁺ transient amplitudes in fluorescence ratio units (F340/F380). Squares indicate ROIs for measurements averaged in panel B. D, Mean baseline ratios. E, Mean Ca²⁺ transient amplitudes. One-way ANOVA, * p<0.05 for comparisons with wild-type (n=9 wild-type zebrafish embryos; n=7 LITAF morphants). Error bars depict SEM.