CDK5RAP3 also known as CDK5 regulatory subunit-associated protein 3. This protein is potential regulator of CDK5 activity via its interaction with CDK5R. Neuronal CDC2-like kinase, which is involved in the regulation of neuronal differentiation, is composed of a catalytic subunit, CDK5, nad an activating subunit, p25NCK5A. CDK5RAP3 binds to p25NCK5A and therefore may be involved in neuronal differentiation. Recombinant human CDK5RAP3, fused to His-tag at N-terminus, was expressed in E.coli and purified by using conventional chromatography techniques.