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PhD Exit Seminar for Julia Gauberg (Senatore Lab)

September 23, 2021 @ 1:00 pm - 2:00 pm

Comparative Analysis of CaV1 and CaV2 Voltage-Gated Calcium Channels from Trichoplax adhaerens Reveals Early Divergence of Channel Types and Biophysical Properties


To translate electrical signals into chemical signals at the synapse, cells employ voltage-gated calcium (CaV) channels. Most animals have three types of CaV channels, CaV1-CaV3, and of these, CaV1 and CaV2 channels have distinct roles at the synapse that are conserved across many animal phyla, from invertebrates to humans. CaV2 channels are involved in exocytosis of vesicles from the presynaptic cell, and CaV1 channels are typically involved in triggering gene transcription or contraction at the postsynaptic cell. CaV1 and CaV2 channels from nematodes to mammals have conserved features that are important for their post-/presynaptic functions, and it is possible that these features are conserved in more early-diverging animals as well. The most early-diverging animal phylum to have all three CaV channel homologues is the Placozoa. Placozoans are microscopic, marine animals that lack true tissues and synapses but still exhibit complex behaviours. Because they lack synapses but have all three types of CaV channels, they can be used as an evolutionary outgroup to examine the properties of CaV1 and CaV2 channels. The work presented in this thesis describes the characterization of the CaV1 and CaV2 channel homologues cloned from the placozoan Trichoplax adhaerens. The T. adhaerens CaV1 (TCaV1) and CaV2 (TCaV2) channels share structural and functional features that differentiate them from the TCaV3 channel.  The biophysical properties of the TCaV channels were found to be more similar to their mammalian homologues than each other. However, differences in modulation by cytosolic proteins such as G-proteins and calmodulin, which are defining features of these channels in mammals, are lacking in TCaV1 and TCaV2 channels. Thus, ancestral CaV1 and Cav2 channels likely diverged in their biophysical properties before gaining the ability to be modulated by different cytosolic proteins. Finally, TCaV1 and TCaV2 channel expression was examined in vivo, revealing that these channels are expressed in cell types that are known to be contractile and neuroendocrine-like. The differences in TCaV1 and TCaV2 expression suggests that they have different functions in vivo. Overall, this work provides invaluable insight into the properties of T. adhaerens CaV channels and contributes to our understanding of metazoan CaV channel evolution.



Thursday, September 23rd, 2021 at 1:00 pm

Join Zoom Meeting


Meeting ID: 841 6597 5470

Host: Adriano Senatore (adriano.senatore@utoronto.ca)



September 23, 2021
1:00 pm - 2:00 pm