Biosynthesis of gp160, the major trypsin-sensitive surface glycoprotein of macrophages

N-terminal sequence of human leukocyte glycoprotein Mo1: conservation across species and homology to platelet IIb/IIIa

Mo1 and gp160-gp93 are two surface membrane glycoprotein heterodimers present on granulocytes and monocytes derived from humans and guinea pigs, respectively. We purified both antigens and found that their alpha subunits had identical N-termini which were significantly homologous to the alpha subunit of the human adhesion platelet glycoprotein IIb/IIIa.

Partial characterization of a transformation-specific glycopeptide in SSV-NP cells

An autologous antiserum against simian sarcoma virus-infected nonproducer cells (SSV-NP cells) recognized a SSV transformation-specific glycopeptide (SSV-TrSgp) [H.-J. Thiel, T.J. Matthews, E.M. Broughton, A.M. Butchko, and D.P. Bolognesi (1981) Virology 112, 642-650]. Gel filtration of this component on a Sephacryl S-200 column indicated an apparent molecular weight at about 200,000 (d). This antigen represented a proteoglycan-like molecule, as evidenced by the size of glycopeptides after Pronase treatment and by incubation with chondroitinases. The antigenicity of the SSV-TrSgp was completely destroyed after exposure to different proteases. On the other hand, incubation with neuraminidase or chondroitinases degraded the molecule to some extent, but did not affect its antigenicity as measured by immunoprecipitation. Trypsin and EDTA treatment of intact pulse-labeled cells, as well as surface iodination, indicated that the SSV-TrSgp represents a cell membrane-associated molecule.