Glycosylphosphatidylinositol-anchored cell-surface proteins from Arabidopsis

Remodeling of the plant cell surface occurs during the establishment of cel l polarity, cellular differentiation, and organ development. This report de monstrates the existence of multiple glycosylphosphatidylinositol (GPI)-anc hored proteins in the model plant Arabidopsis. Using two-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), we also sho w that GPI-anchored proteins are a relatively abundant class of protein and that they are present at the plant plasma membrane. Furthermore, some of t hese proteins are released into the extracellular matrix. At least one of t hese is an arabinogalactan protein (AGP), a class of proteins known to be a ssociated with cellular differentiation. Analysis of the amino acid sequenc es of two novel AGP-like proteins from Arabidopsis predicts that these prot eins contain consensus signals for GPI-anchor addition. These findings supp ort a model where GPI-anchored proteins are involved in the generation of s pecialized cell surfaces and extracellular signaling molecules.