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Mannosamine, a novel inhibitor of glycosylphosphatidylinositol incorporation into proteins.
Author(s) -
Lisanti M.P.,
Field M.C.,
Caras I.W.,
Me A.K.,
RodriguezBoulan E.
Publication year - 1991
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1002/j.1460-2075.1991.tb07726.x
Subject(s) - biology , computational biology , biochemistry , microbiology and biotechnology
Mannosamine (2‐amino‐2‐deoxy D‐mannose) is shown here to block the incorporation of glycosylphosphatidylinositol (GPI) into GPI‐anchored proteins. The amino sugar drastically reduced the surface expression of a recombinant GPI‐anchored protein in polarized MDCK cells, converted this apical membrane‐bound protein to an unpolarized secretory product and blocked the expression of endogenous GPI‐anchored proteins. Furthermore, it specifically inhibited the incorporation of [3H]ethanolamine (a GPI component) into mammalian and trypanosomal GPI‐anchored proteins and into a well characterized GPI‐lipid of Trypanosoma brucei. These results suggest that mannosamine converted an apical GPI‐anchored protein to a non‐polarized secretory product by depleting transfer competent GPI‐precursor lipids. Our inhibitor studies provide new independent evidence for the apical targeting role of GPI in polarized epithelia and open the way towards a greater understanding of the functional role of GPI in membrane trafficking and cell regulation.