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Müller, Günter; Schubert, Karin; Fiedler, Franz; Bandlow, Wolfhard
(1992):
The CAMP-binding Ectoprotein from Saccharomyces cereuisiae Is Membrane-anchored by Glycosyl-Phosphatidylinositol.
In: Journal of Biological Chemistry, Vol. 267: pp. 25337-25346
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![[img]](https://epub.ub.uni-muenchen.de/3138/1.hassmallThumbnailVersion/001.pdf)  Preview |
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Abstract
Saccharomyces cerevisiae contains an amphiphilic
CAMP-binding glycoprotein at the outer face of the
plasma membrane (M, = 54,000). It is converted to a
hydrophilic form byt reatment withg lycosyl-phosphatidylinositol-
specific phospholipases C and D (GPIPLC/
D), suggesting membrane anchorage by a covalently
bound glycolipid. Determination of the constituents
of the purified anchor by gas-liquid chromatography
and amino acid analysis reveals the presence of
glycerol, myo-inositol, glucosamine, galactose, mannose,
ethanolamine, and asparagine (as the carboxylterminal
amino acido f the Pronase-digested proteitno
which the anchor is attached). Complementary results
are obtained by metabolic labeling, indicating that
fatty acids and phosphorus are additional anchor constituents.
The phosphoruiss resistant to alkalinep hosphatase,
whereas approximately half is lost from the
protein after treatment with GPI-PLD or nitroaucisd ,
and all is removed by aqueous HF indicating the presence
of two phosphodiester bonds. Inhibition of Nglycosylation
by tunicamycin or removal of proteinbound
glycan chains by N-glycanase or Pronase does
not abolish radiolabeling of the anchor structure by
any of the above compounds. Analysis of the products
obtained after sequential enzymic and chemical degradation
of the anchor agrees with the arrangemoefn t
constitutents in GPIs from higher eucaryotes. Evidence
for anchorage of the yeast CAMP-binding protein by a
GPI anchoris strengthened additionallyb y the reactivity
of the GPI-PLC-cleaved anchor with antibodies
directed against the cross-reacting determinoaf nttr ypanosomal
variant surface glycoproteins.
