Transplantation Biology Section, Clinical Research Centre, Harrow, Middlesex, UK.
A number of lymphocyte proteins are attached to the cell membrane via glycophosphatidylinositol-anchoring domains. Antibodies specific for several of these proteins are potent mitogens for T cells. In this article, Peter Robinson reviews recent evidence for the involvement of these membrane anchors in cell signalling events and discusses their possible significance in providing antigen-independent costimulatory signals to lymphoid cells.