GPI-ANCHORS ON ARABINOGALACTAN-PROTEINS - IMPLICATIONS FOR SIGNALING IN PLANTS

Arabinogalactan-proteins are a class of hydroxyproline-rich proteoglyc ans implicated in plant growth and development. A major challenge is t o establish how this structurally complex family of cell surface molec ules regulates processes such as cell proliferation and somatic embryo genesis. The recent report that two 'classical' arabinogalactan-protei ns have a glycosylphosphatidylinositol-(GPI-)member anchor, offers a n ew framework for considering their mode of action. Drawing on knowledg e from other eukaryotic systems (animals, yeast and parasitic protozoa ), we suggest potential mechanisms for the involvement of GPI-membrane anchored arabinogalactan-proteins in signal transduction pathways.