KLC1 and early-onset autosomal dominant Alzheimer disease: To investigate how phosphorylation of KLC1 serine-460 might contribute to Alzheimer’s disease, we quantified axonal transport of APP-EGFP using time-lapse microscopy in living rat cortical neurons that were co-transfected with either FLAG-KLC1wt or FLAG-KLC1S460D in which serine-460 was mutated to aspartic acid to mimic permanent phosphorylation.