DPYSL2 and early-onset autosomal dominant Alzheimer disease: For instance, while CDK5 normally phosphorylates collapsin response mediator protein 2 (CRMP2) to stimulate axon growth, it was found that hyperphosphorylation of CRMP2, as well as Tau, were implicated in the generation of neurofibrillary tangles characteristic of Alzheimer's disease [53].