title: Cell surface sialylation plays a role in modulating sensitivity towards APO-1-mediated apoptotic cell death.
abstract: APO-1/Fas(CD95), a member of the tumour necrosis factor (TNF)/nerve growth factor (NGF) receptor superfamily transduces apoptotic signals into apoptosis sensitive cells. In metabolic labelling experiments using the highly APO-1 positive cell lines HUT78 (adultT cell leukemia) and SKW6.4 (Blymphoblastoid cell line) APO-1 was characterised as a long living protein with a complex glycosylation pattern involving terminal sialic acid groups which account for 8-kDa of its apparent molecular weight on SDS-PAGE. APO-1 expression and the degree of sialylation were determined in additionalT and B cell lines. On the group I Burkitt's lymphoma cell line BL60 transfected with human APO-1 (K50) low sialylated species were detected only on the cell surface, suggesting that sialylation might be functionally important. Removal of terminal sialic acid groups by treatment of B and T cell lines with Vibrio cholerae neuraminidase (VCN) augmented sensitivity towards anti-APO-1 and human APO-1 ligand induced apoptosis. Similarly, VCN-treated U937 cells were rendered more sensitive to TNFalpha-induced cell death. Thus, sialylation may be one mechanism to regulate sensitivity towards ligand-mediated cell death in this receptor family.
authors.affiliation: German Cancer Research Center, Tumour Immunology Programme, Im Neuenheimer Feld 280, D-69120 Heidelberg, Germany.
authors.forename: M E
authors.initials: ME
authors.lastname: Peter
authors.forename: S
authors.initials: S
authors.lastname: Hellbardt
authors.forename: R
authors.initials: R
authors.lastname: Schwartz-Albiez
authors.forename: M O
authors.initials: MO
authors.lastname: Westendorp
authors.forename: H
authors.initials: H
authors.lastname: Walczak
authors.forename: G
authors.initials: G
authors.lastname: Moldenhauer
authors.forename: M
authors.initials: M
authors.lastname: Grell
authors.forename: P H
authors.initials: PH
authors.lastname: Krammer