Sugary secrets of a cancer-related protein
Protein glycosylation is either called N-linked or O-linked, depending on whether the sugar is attached to nitrogen- or oxygen-containing sites, respectively. O-linked modifications typically involve the sugar N-acetylgalactosamine being attached to the amino acids serine or threonine, called "mucin-type" glycosylaton because they are commonly found in proteins in mucus membranes; together with N-linked sugars, these " canonical " modifications modify thousands of different types of proteins. For over 20 years, Robert Haltiwanger's research group, now at the University of Georgia, has studied much rarer type of O-linked modifications: attachment of the sugars glucose or fucose to serine or threonine, a modification that affects just a few hundred different types of proteins. One of these proteins is Notch, a signaling receptor that is essential for cell development and differentiation and is dysregulated in cancers such as leukemia, breast cancer, and prosta...