Expression of Ca²⁺ channels in X. laevis eggs. Heatmaps of RNA (left) and protein (Prot; right) expression levels of Ca²⁺ channels whose transcript levels were >1 TPM. Transcript levels (shown as TPM) were obtained from Session et al. (2016). Protein concentrations are from Wühr et al. (2014) as determined by mass spectrometry (mass spec.)–based proteomics in log₂ nanomolar. Red arrows highlight plasma membrane localized Ca²⁺ channels found in eggs.