- The collapsin response mediator protein 1 (CRMP-1) and the promyelocytic leukemia zinc finger protein (PLZF) bind to UDP-N-acetylglucosamine 2-epimerase/N-acetylmannosamine kinase (GNE), the key enzyme of sialic acid biosynthesis. Weidemann, W., Stelzl, U., Lisewski, U., Bork, K., Wanker, E.E., Hinderlich, S., Horstkorte, R. FEBS Lett. (2006)