CAPS1 Deficiency Perturbs Dense-Core Vesicle Trafficking and Golgi Structure and Reduces Presynaptic Release Probability in the Mouse Brain

T. Sadakata, W. Kakegawa, Y. Shinoda, M. Hosono, R. Katoh-Semba, Y. Sekine, Y. Sato, M. Tanaka, T. Iwasato, S. Itohara, K. Furuyama, Y. Kawaguchi (+3 others)
2013 Journal of Neuroscience  
Ca(2+)-dependent activator protein for secretion 1 (CAPS1) plays a regulatory role in the dense-core vesicle (DCV) exocytosis pathway, but its functions at the cellular and synaptic levels in the brain are essentially unknown because of neonatal death soon after birth in Caps1 knock-out mice. To clarify the functions of the protein in the brain, we generated two conditional knock-out (cKO) mouse lines: 1) one lacking Caps1 in the forebrain; and 2) the other lacking Caps1 in the cerebellum. Both
more » ... he cerebellum. Both cKO mouse lines were born normally and grew to adulthood, although they showed subcellular and synaptic abnormalities. Forebrain-specific Caps1 cKO mice showed reduced immunoreactivity for the DCV marker secretogranin II (SgII) and the trans-Golgi network (TGN) marker syntaxin 6, a reduced number of presynaptic DCVs, and dilated trans-Golgi cisternae in the CA3 region. Cerebellum-specific Caps1 cKO mice had decreased immunoreactivity for SgII and brain-derived neurotrophic factor (BDNF) along the climbing fibers. At climbing fiber-Purkinje cell synapses, the number of DCVs was markedly lower and the number of synaptic vesicles was also reduced. Correspondingly, the mean amplitude of EPSCs was decreased, whereas paired-pulse depression was significantly increased. Our results suggest that loss of CAPS1 disrupts the TGN-DCV pathway, which possibly impairs synaptic transmission by reducing the presynaptic release probability.
doi:10.1523/jneurosci.2777-13.2013 pmid:24174665 pmcid:PMC6618362 fatcat:gameit4lm5ez5oy5obmfhab5sy