Biosynthesis of phosphatidylinositol-glycan (PI-G)-anchored membrane proteins in cell-free systems: PI-G is an obligatory cosubstrate for COOH-terminal processing of nascent proteins.
AUTOR(ES)
Kodukula, K
RESUMO
It is generally recognized that nascent proteins destined to be processed to a phosphatidylinositol-glycan (PI-G)-anchored membrane form contain a hydrophobic signal peptide at both their NH2 and COOH termini. In previous studies we showed that rough microsomal membranes (RM) prepared from CHO cells can carry out COOH-terminal processing. We have now investigated RM prepared from many additional cell types, including frog oocytes, B cells, and T cells, and found that all are competent with respect to COOH-terminal processing. Exceptions were certain mutant T cells that had been shown to be defective at various steps of PI-G anchor biosynthesis [Sugiyama, E., De Gasperi, R., Urakaze, M., Chang, H.-M., Thomas, L. J., Hyman, R., Warren, C. D. & Yeh, E. T. H. (1991) J. Biol. Chem. 266, 12119-12122]. In one such defective mutant, COOH-terminal processing activity of RM could be restored either by transfecting the intact cells with the gene for the deficient step in PI-G synthesis or by adding PI-G extracts to the RM in vitro. Cleavage of the COOH-terminal signal peptide in the RM is therefore dependent on the presence of intact PI-G incorporated into the mature protein.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=49212Documentos Relacionados
- Biosynthesis of phosphatidylinositol-glycan (PI-G)-anchored membrane proteins in cell-free systems: cleavage of the nascent protein and addition of the PI-G moiety depend on the size of the COOH-terminal signal peptide.
- Phosphatidylinositol-glycan (PI-G)-anchored membrane proteins: requirement of ATP and GTP for translation-independent COOH-terminal processing.
- Selectivity at the cleavage/attachment site of phosphatidylinositol-glycan anchored membrane proteins is enzymatically determined.
- Characterization of the phosphatidylinositol-glycan membrane anchor of human placental alkaline phosphatase.
- Cholecystokinin and its COOH-terminal octapeptide in the pig brain.