c-Jun localizes to the nucleus independent of its phosphorylation by and interaction with JNK and vice versa promotes nuclear accumulation of JNK

► HSP70, Ku70 and 80 as well as importin 8 are novel interactors of c-Jun. ► Nuclear accumulation of c-Jun does not require its functions as a transcription factor. ► Nuclear accumulation of c-Jun does not require the interaction with its kinase JNK. ► Nuclear accumulation of JNK is regulated by interaction with c-Jun.