Negatively regulates Golgi-to-plasma membrane trafficking by interacting with PI4KB and inhibiting its activity. May play a role in the physiology of neurons and is potentially important in memory and learning. Interacts with PI4KB. This binding competes with FREQ/NCS1 binding in a calcium-dependent manner. Brain-specific. High expression in the cerebellum, hippocampus, and cortex. The C-terminal transmembrane domain (TMD) is necessary and sufficient for membrane targeting. Calcium binding induces conformational changes in CALN1/CABP8. The calcium binding affinity is not regulated by magnesium.