Lawrence Tabak, D.D.S., Ph.D.

Dr. Lawrence Tabak's laboratory studies the functions and biosynthesis of O-glycans. Mucin-glycoproteins are heavily decorated with carbohydrate side-chains, termed O-glycans, which are often clustered within repeating amino acids sequences of the protein (tandem repeats). Functionally, membrane-bound mucins are involved in signal transduction events, whereas secreted mucins contribute to the formation of extracellular matrix or to the gel-like mucus coat which envelopes mucosal surfaces of the body thereby forming the most exterior face of the innate immune system. Although it is known that O-glycans are ubiquitous among proteins, the precise nature of the “O-glycome” remains to be defined. We have approached this by both top-down and bottom-up proteomic studies as well as investigations of the substrate specificities of the multi-gene family of enzymes that are responsible for the formation of O-glycans, the UDP-GalNAc:polypeptide N-Acetylgalactosaminyltransferases (GalNAcTs).