For immunostaining, neuronal cells on the coverslips were first fixed in PBS containing 4% paraformaldehyde (PFA) for 12 hrs at 4°C and then incubated in a solution containing 4% PFA and 0.4% Triton X-100 at 4°C for 1 hr. After washing with PBS three times, the cells were incubated with a blocking solution containing 1:30 normal goat serum, and subsequently incubated with a rabbit polyclonal anti-ACDP antibody (1:3000) overnight at 4°C. After extensive washing with 1% goat serum PBS solution, the cells were incubated with an Alex 488 conjugated secondary antibody (1:100 in 1% goat serum PBS solution, Molecular Probes) for 3 hrs at room temperature. Following final washes with 1% goat serum PBS solution, the neuronal cells on the coverslips were cover-slipped with a glycerol-based anti-photobleach medium. The cells were viewed under a confocal microscope (Carl Zeiss). Images were captured with a CCD camera and acquired by the Scion Image software (Scion Corporation, Frederick, MD).