Fig. 1. Functions of p97/Cdc48p. Some functions of p97 are described, including those that occur in interphase (top) and those that are restricted to telophase (bottom). The appropriate adaptor for each activity (where known) is identified. (A) Retrotranslocation of unfolded proteins from the endoplasmic reticulum (ER); unfolded proteins are passed back through the Sec61 translocon (green) and released by p97 so that they can be degraded by the proteasome. (B) Formation of tER; p97 supports homotypic fusion of smooth ER membranes required to form post-ER transport intermediates. (C) Activation of SPT23; the proteasome degrades the C-terminal portion of SPT23, whilst p97 releases the N-terminal product from its full-length SPT23-binding partner so that it can be transported to the nucleus. (D) Nuclear factor B (NFB) activation; p97 cooperates in an unknown way with the proteasome to degrade the regulatory factor IB, allowing NFB (pink) to enter the nucleus. (E) Reformation of Golgi cisternae from tubulo-vesicular clusters occurs as the cell exits mitosis [note that another AAA protein, N-ethylmaleimide-sensitive fusion protein (NSF), is required in addition to p97 for full Golgi stack reassembly]. (F,G) Nuclear envelope reassembly; this occurs in two phases, resealing of the nuclear envelope (requiring Ufd1–Npl4–p97) and expansion (requiring p47–p97).