The balanced growth of a cell requires the integration of major systems such as 
DNA replication, membrane biosynthesis, and ribosome formation. An example of 
such integration is evident from our recent finding that, in Saccharomyces 
cerevisiae, any failure in the secretory pathway leads to severe repression of 
transcription of both rRNA and ribosomal protein genes. We have attempted to 
determine the regulatory circuit(s) that connects the secretory pathway with the 
transcription of ribosomal genes. Experiments show that repression does not 
occur through the circuit that responds to misfolded proteins in the endoplasmic 
reticulum, nor does it occur through circuits known to regulate ribosome 
synthesis, e.g. the stringent response, or the cAMP pathway. Rather, it appears 
to depend on a stress response at the plasma membrane that is transduced through 
protein kinase C (PKC). Deletion of PKC1 relieves the repression of both 
ribosomal protein and rRNA genes that occurs in response to a defect in the 
secretory pathway. We propose that failure of the secretory pathway prevents the 
synthesis of new plasma membrane. As protein synthesis continues, stress 
develops in the plasma membrane. This stress is monitored by Pkc1p, which 
initiates a signal transduction pathway that leads to repression of 
transcription of the rRNA and ribosomal protein genes. The importance of the 
transcription of the 137 ribosomal protein genes to the economy of the cell is 
apparent from the existence of at least three distinct pathways that can effect 
the repression of this set of genes.