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 nuclear import and relocates nuclear proteins to the cytoplasm. sec mutants also relocate nucleoporins; however, endocytic and Golgi-to-vacuole transport mutants do not cause relocation. The ASR requires Wsc membrane proteins that are trapped along the secretory path, rather than those which are at the plasma membrane. The activity of the downstream kinase, Pkc1p, is also required; however, the Pkc1p MAP kinase cascade is not. sec mutants initiate compensatory transcriptional changes distinct from those of the unfolded protein response.