In vitro synthesis of vesicular stomatitis virus membrane glycoprotein and insertion into membranes.

AUTOR(ES)

Toneguzzo, F

RESUMO

Translation in vitro of the mRNA coding for the vesicular stomatitis virus membrane glycoprotein G in a membrane-free ribosomal extract from HeLa cells allowed the synthesis of only the unglycosylated protein G1 (molecular weight, 63,000). Addition of stripped crude microsomal membranes from HeLa cells resulted in the conversion of G1 to the glycosylated protein G2 (molecular weight, 67,000). The G2 protein synthesized by the reconstructed microsomal membrane/ribosome system was found to be segregated inside the microsomal membrane vesicles and was thus protected from the proteolytic action of trypsin and chymotrypsin. Stripped membranes were required at an early stage of protein synthesis for the synthesized protein to be inserted into the membrane vesicles and to be glycosilated. The segregated protein G2, however, was not completely protected from proteolytic digestion, showing that a portion of the polypeptide chain of about 3000 daltons was present on the cytoplasmic side of the membrane vesicle. Our data thus suggest that, unlike the secretory proteins, the membrane glycoproteins are not completely discharged across the microsomal membranes.

Documentos Relacionados

• Herpesvirus glycoprotein synthesis and insertion into plasma membranes.
• Synthesis and glycosylation in vitro of glycoprotein of vesicular stomatitis virus.
• Assembly of viral membranes. I. Association of vesicular stomatitis virus membrane proteins and membranes in a cell-free system.
• Synthesis and insertion of cytochrome P-450 into endoplasmic reticulum membranes.
• Assembly of viral membranes: nature of the association of vesicular stomatitis virus proteins to membranes.