ISSN:
1365-2958
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Biology
,
Medicine
Notes:
We constructed hybrid proteins containing a plant α-galactosidase fused to various C-terminal moieties of the hypoxic Srp1p; this allowed us to identify a cell wall-bound form of Srp1p. We showed that the last 30 amino acids of Srp1p, but not the last 16, contain sufficient information to signal glycosyl-phosphatidylinositol anchor attachment and subsequent cell wall anchorage. The cell wall-bound form was shown to be linked by means of a β1,6-glucose-containing side-chain. Pmt1p enzyme is known as a protein-O-mannosyltransferase that initiates the O-glycosidic chains on proteins. We found that a pmt1 deletion mutant was highly sensitive to zymolyase and that in this strain the α-galactosidase–Srp1 fusion proteins, an α-galactosidase–Sed1 hybrid protein and an α-galactosidase–α-agglutinin hybrid protein were absent from both the membrane and the cell wall fractions. However, the plasma membrane protein Gas1p still receives its glycosyl-phosphatidylinositol anchor in pmt1 cells, and in this mutant strain an α-galactosidase–Cwp2 fusion protein was found linked to the cell wall but devoid of β1,6-glucan side-chain, indicating an alternative mechanism of cell wall anchorage.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1046/j.1365-2958.1998.00660.x
