GPI-anchors: An overview

Over the last ten years since the discovery of GPI-anchoring as an alternative principle of membrane anchoring of proteins the research on these anchors has expanded dramatically. An enormous body of knowledge about their structure, biosynthesis and function has accumulated. Several systems have been studied, ranging from protozoa, yeast to mammalian cell lines, to elaborate this information. Analysis on the functional level revealed that GPIs exhibit a variety of functions beyond their mere function as membrane anchors e.g. in the maturation and transport of membrane proteins or their role in signal transduction processes and as pathogenicity factors. The recognition site for the transfer of the GPI-anchor to the native protein by the so called GPI-transamidase has been determined by the combination of biochemical and molecular genetic methods. Mutant cell lines and yeast strains with defined defects in the pathway of GPI-biosynthesis allowed the identification of the genes involved and have led to the successful cloning of several such genes. These key subjects will be dealt with in this article.