Editors' ChoiceCell Biology

Tied into Protein Degradation

STKE  11 Jan 2000:
Vol. 2000, Issue 14, pp. tw8
DOI: 10.1126/stke.2000.14.tw8

The list of key signaling events that are regulated by controlled ubiquitin-dependent degradation of proteins continues to grow. Brondello et al. report that MAP kinase phosphatase-1 (MKP-1), which dephosphorylates and inactivates the p42 and p44 mitogen-activated protein (MAP) kinases, is degraded by the proteasome. The phosphatase itself is a target of the p42 MAPK and p44 MAPK enzymes that it inactivates. This phosphorylation of MKP-1 appears not to regulate its enzymatic activity, but rather to decrease its ubiquitin-dependent degradation. The MAP kinases also increase transcription of the gene encoding MKP-1, thus providing two signals that increase the abundance of MKP-1. Such regulation would appear to limit prolonged activation of the p42 and p44 MAP kinases.

Brondello, J-M., Pouysségur, J., and McKenzie, F.R. (1999) Reduced MAP kinase phosphatase-1 degradation after p42/p44MAPK-dependent phosphorylation. Science 286: 2514-2517. [Abstract] [Full Text]