Disruption of α-mannosidase processing induces non-canonical hybrid-type glycosylation

Golgi alpha-mannosidase 11 is essential for the efficient formation of complex-type glycosylation. Here, we demonstrate that the disruption of Golgi a-mannosidase 11 activity by swainsonine in human embryonic kidney cells is capable of inducing a novel class of hybrid-type glycosylation containing a partially processed mannose moiety. The discovery of 'Man(6)-based' hybrid-type glycans reveals a broader in vivo specificity of Nacetylglucosaminyltransferase 1, further defines the arm-specific tolerance of core alpha 1-6 fucosyltransferase to terminal a1-2 mannose residues, and suggests that disruption of Golgi a-mannosidase 11 activity is capable of inducing potentially 'non-self' structures. (C) 2007 Published by Elsevier B.V. on behalf of the Federation of European Biochemical Societies.