The arrest of secretion response in yeast: Signaling from the secretory path to the nucleus via Wsc proteins and Pkc1p

The arrest of secretion response (ASR) in sec mutants reversibly inhibits n uclear import and relocates nuclear proteins to the cytoplasm. sec mutants also relocate nucleoporins; however, endocytic and Golgi-to-vacuole transpo rt mutants do not cause relocation. The ASR requires Wsc membrane proteins that are trapped along the secretory path, rather than those which are at t he plasma membrane. The activity of the downstream kinase, Pkc1p, is also r equired; however, the Pkc1p MAP kinase cascade is not. sec mutants initiate compensatory transcriptional changes distinct from those of the unfolded p rotein response.