Figure 3

Expression profile and glycosylation pattern of neurexin-1β in human embryonic kidney 293 (HEK293) cells. A. Expression profiles of neurexin-1β-1’ (Nrxn -1β-1’) in total cell lysate of HEK293 cells that had been transfected with neurexin-1β-1’-His or synaptic acetylcholinesterase (AChE-S) or both. Neurexin-1β-1’ proteins were confirmed by anti-His. B. Expression profiles of neurexin-1β-1’ in the membrane fractions of HEK293 cells that had been transfected with neurexin-1β-1’-His alone or AChE-S alone or both. In both A and B, blotting His revealed multiple bands of neurexin-1β-1’. Notably, co-transfection with AChE decreased the expression of neurexin-1β in the HEK293 cells. C. Left panel: Immunoblots of neurexin-1β-1’ generated by processing the cell lysates with various N- and O-glycohydrolases (N = peptide N-glycosidase F, an N-linked glycohydrolase; O = O-glycosidase and S = sialidase, two O-linked glycohydrolases). Right panel: Immunoblots of neurexin-1β-1’ generated by processing lysates of transfected HEK293 cells without additional treatment (vehicle control [ctrl]) or with tunicamycin treatment (Tunic.). Note the similar change in molecular weight of the neurexin-1β-1’ bands following treatment with N-glycosidase F and tunicamycin.