IMMEDIATE-EARLY RESPONSE OF THE P62 GENE ENCODING A NON-PROTEASOMAL MULTIUBIQUITIN CHAIN BINDING-PROTEIN

p62 is a cytoplasmic ubiquitin chain binding protein. Upon a variety o f extracellular signals, both transcript and protein levels of p62 mer e rapidly increased. These signals include phorbol 12-myristate 13-ace tate (PMA) and calcium ionomycin for peripheral blood mononuclear cell s, serum or PDGF for serum-starved NIH3T3 cells, IL-3 for the G1 arres ted pre-B cell line Ba/F3, and PMA for a human promyelocyte line U937, The elevation of p62 transcript level is due to temporal stabilizatio n of mRNA and rapid activation of the p62 gene. Cycloheximide-induced enhanced transcription suggests the immediate early response of the p6 2 gene. The rapid induction of p62 indicates the presence of a novel u biquitination-mediated regulatory mechanism during cell proliferation and differentiation. (C) 1998 Federation of European Biochemical Socie ties.