Stress-induced nuclear import of apoptosis signal-regulating kinase 1 is mediated by karyopherin α2/β1 heterodimer

► ASK1 translocates from the cytoplasm to the nucleus in response to stress. ► Karyopherin α2/β1 heterodimer physically interacts with ASK1 via a newly identified NLS motif, facilitating ASK1 nuclear entry. ► In response to stress, active nuclear ASK1 participates in cytotoxicity. ► Stress-induced ASK1 nuclear import is a novel mechanism for controlling ASK1 function.