UBIQUITIN-LIKE EPITOPES ASSOCIATED WITH CANDIDA-ALBICANS CELL-SURFACERECEPTORS

We have recently reported the cloning of a Candida albicans polyubiqui tin gene and the presence of ubiquitin in the cell wall of this fungus . The polyubiquitin cDNA clone was isolated because of its reactivity with antibodies generated against the candidal 37-kDa laminin-binding protein. In the present study, we have further investigated the relati onship between ubiquitin and cell wall components displaying receptor- like activities, including the 37-kDa laminin receptor, the 58-kDa fib rinogen-binding mannoprotein, and the candidal C3d receptor. Two-dimen sional electrophoretic analysis and immunoblot experiments with antibo dies against ubiquitin and the individually purified receptor-like mol ecules confirmed that these cell surface components are ubiquitinated, In an enzyme-linked immunosorbent assay, polyclonal antisera to each receptor reacted with ubiquitin, thus demonstrating that the purified receptor preparations used as immunogens contained ubiquitin-like epit opes, It is proposed that ubiquitin may play a role in modulating the activity of these receptors and in the interaction of C. albicans cell s with host structures.