Schizophrenia is a debilitating neurological disease, with many genetic causes that are not well known. During a genome-wide association study and a study of de novo variants, the CACNA1I gene was identified as a significant risk factor for schizophrenia. CACNA1I encodes the T-type voltage-gated calcium ion channel protein known as Cav3.3, which is primarily expressed in the cortex, thalamic reticular nucleus, and hippocampus. Certain de novo mutations in CACNA1I affect the intracellular trafficking of Cav3.3 and appear to be linked to schizophrenia. Little is understood about the mechanism of Cav3.3 in schizophrenia; we aim to provide insight about its function by optimizing methods of purifying the protein and by determining its localization in the neuron. Although large ion channels such as Cav3.3 are notoriously difficult to isolate in large quantities, we have developed a method of purifying Cav3.3 through immunoprecipitation. We plan to use this process for mass spectrometry and cryo-electron microscopy in order to better characterize the trafficking mechanisms and structure of Cav3.3. Additionally, by using neuronal culture, we have localized Cav3.3 by comparing the immunofluorescence of marker proteins with endogenous Cav3.3. Our preliminary results indicate that Cav3.3 is expressed in the postsynaptic region of synapses, as well as in inhibitory neurons. These insights about the function of Cav3.3 can help elucidate the genetic and molecular mechanisms of schizophrenia, and in the future may aid in the development of novel neuropharmacological treatments.
PROJECT: Purification and localization of Cav3.3, a protein implicated in schizophrenia genetics
SRPG has been one of the most challenging and rewarding experiences I’ve ever had. It is rare that undergraduate students are able to work on summer projects at the cutting edge of scientific research, but at SRPG it is the norm. I know that the skills and relationships I have developed here, both in and out of the lab, will be with me for the rest of my scientific career.