Sendai-viral HN and F glycoproteins as probes of plasma-membrane protein catabolism in HTC cells. Studies with fusogenic reconstituted Sendai-viral envelopes.
Reconstituted Sendai-viral envelopes (RSVE) were produced by the method of Vainstein, Hershkovitz, Israel & Loyter [(1984) Biochim. Biophys. Acta 773, 181-188]. RSVE are fusogenic unilamellar vesicles containing two transmembrane glycoproteins: the HN (haemagglutinin-neuraminidase) protein and the F (fusion) factor. The fate of the viral proteins after fusion-mediated transplantation of RSVE into hepatoma (HTC) cell plasma membranes was studied to probe plasma-membrane protein degradation. Both protein species are degraded at similar, relatively slow, rates (t1/2 = 67 h) in HTC cells fused with RSVE in suspension. Even slower degradation rates for HN and F proteins (t1/2 = 93 h) were measured when RSVE were fused with HTC cells in monolayer. Lysosomal degradation of the transplanted viral proteins is strongly implicated by the finding that degradation of HN and F proteins is sensitive to inhibition by 10 mM-NH4Cl (81%) and by 50 micrograms of leupeptin/ml (70%).
D000643:Ammonium Chloride / Q000494:pharmacology; D000818:Animals; D001386:Azides / Q000494:pharmacology; D002460:Cell Line; D004279:DNA, Viral / Q000378:metabolism; D003847:Deoxyglucose / Q000494:pharmacology; D015707:HN Protein; D006389:Hemagglutinins, Viral / Q000378:metabolism*; D007976:Leupeptins / Q000494:pharmacology; D008114:Liver Neoplasms, Experimental / Q000473:pathology; D008561:Membrane Fusion; D008565:Membrane Proteins / Q000378:metabolism*; D010222:Parainfluenza Virus 1, Human / Q000378:metabolism*; D019810:Sodium Azide; D014759:Viral Envelope Proteins / Q000378:metabolism*; D014760:Viral Fusion Proteins / Q000378:metabolism*
D001386:Azides; D004279:DNA, Viral; D015707:HN Protein; D006389:Hemagglutinins, Viral; D007976:Leupeptins; D008565:Membrane Proteins; D014759:Viral Envelope Proteins; D014760:Viral Fusion Proteins; D000643:Ammonium Chloride; D019810:Sodium Azide; D003847:Deoxyglucose; C032854:leupeptin