A Candida albicans 37 kDa polypeptide with homology to the laminin receptor is a component of the translational machinery

A cDNA encoding a 37 kDa protein was isolated from an expression library using antibodies raised against mycelial cell walls from Candida albicans. The 37 kDa protein has over 60% sequence identity with the 37 kDa laminin-binding protein (LBP) from humans and over 80% identity with the Yst proteins of Saccharomyces cerevisiae. The C. albicans protein was named CaYst1. It was found in membrane and ribosome fractions but surprisingly, was not found in cell walls. Unlike the human LBP, CaYst1p does not bind laminin. These data indicate that CaYst1p is not a cell-surface receptor for laminin as has been proposed for the human LBP. Instead, like the S. cerevisiae Yst proteins, it appears to be a ribosomal protein. This conclusion is supported by the finding that CaYST1-cDNA complements the lethal phenotype linked to the disruption of both YST genes in S. cerevisiae.