REGULATION OF N-ACETYLGLUCOSAMINYLTRANSFERASE-V AND ASN-LINKED OLIGOSACCHARIDE BETA(1,6) BRANCHING BY A GROWTH-FACTOR SIGNALING PATHWAY ANDEFFECTS ON CELL-ADHESION AND METASTATIC POTENTIAL

Recent evidence demonstrates that the changes in the size of N-linked oligosaccharides that correlate with cell transformation and tumorigen icity are due at least in part to the regulation of expression of a gl ycosyltransferase involved in the branching of N-linked structures, N- acetylglucosaminyltransferase V or GlcNAc-T V. Studies have shown that the increases in GlcNAc-T V expression after oncogenic transformation are most likely caused by direct effects on the GlcNAc-T V promoter b y the Ets family of transcriptional activators, which are up-regulated by a cellular proliferation signaling pathway. This pathway begins wi th growth factor receptors that activate tyrosine kinases at the cell surface and proceeds through src, ras, and raf. Additional evidence fo r the association between cellular proliferation and GlcNAc-T V expres sion will be presented, as well as a discussion of the effects of beta (1,6) branching on several of the phenotypes of oncogenically transfor med cells, including metastatic potential.