p62 is a cytoplasmic protein which was originally identified as a tigand of the SH2 domain of p561ck and binds to ubiquitin non-covalently. The generate organization of p62 gene and its response to a variety of signals have been studied, p62 gene is located on the human chromosome 5q35, and its functional promoter lacks both TATA and CAAT boxes but has two GC boxes, four SPI sites and several growth responsive elements. A variety of proliferation and differentiation signals rapidly induced both transcript and protein levels of p62. These include phorbol 12-myristate 13-acetate (PMA) and calcium ionomycin for peripheral blood mononuclear cells (PBMC), serum or PDGI'" for the serum-starved NIH3T3 cells, tL-3 for the early G1 arrested pre-B cell line Be/F3, and PMA for U937. The drastic elevation of p62 levels is due to temporal stabilization of p62 mRNA and rapid transcriptional activation of p62 gene. Cycloheximide-induced superactivation of p62 transcription suggests that p62 is an immediate early response gene product. The ubiquitin binding of p62 and the immediate early response of its gene indicate that p62 has essential function in cell proliferation and differentiation at least partly by controlling protein degradation. This study was supported by grants NIH GM 4896 and ACS CN84478.
|Original language||English (US)|
|State||Published - Dec 1 1997|
ASJC Scopus subject areas
- Molecular Biology