A novel protein phosphatase 2C family member (PP2Cζ) is able to associate with ubiquitin conjugating enzyme 9¹

Abstract

In this study we have cloned a novel member of mouse protein phosphatase 2C family, PP2Cj j, which is composed of 507 amino acids and has a unique N-terminal region. The overall similarity of the amino acid sequence between PP2Cj j and PP2CK K was 22%. On Northern blot analysis PP2Cj j was found to be expressed speci¢cally in the testicular germ cells. PP2Cj j expressed in COS7 cells was able to associate with ubiquitin conjugating enzyme 9 (UBC9) and the association was enhanced by co-expression of small ubiquitin-related modi¢er-1 (SUMO-1), suggesting that PP2Cj j exhibits its speci¢c role through its SUMO-induced recruitment to UBC9. ß

Substrate-dependent metal preference of PPM1H, a cancer-associated protein phosphatase 2C: comparison with other family members

“…Conversely, although the sequence of PPM1H within the catalytic motifs is highly similar to that of PP2Cf and g (Fig. 4), unlike PPM1H, the activity of the former PP2C toward casein is indistinguishable with either metal ion (Kashiwaba et al 2003), whereas the latter achieves a greater phosphatase activity toward casein with Mn 2? (Komaki et al 2003).…”

“…is favorable with casein as a Marley et al (1996) Casein Mg 2? Kashiwaba et al (2003) bPP2Cb Phosphopeptide Mg 2? Krieglstein et al (2003) Casein Mn 2?…”

“…Travis and Welsh (1997) rPP2Cd MyBP Mn 2? Tong et al (1998) Kashiwaba et al (2003) PP2C enzymes shown in Fig. 4 are compiled for comparison in terms of the substrate-dependent metal preference.…”

“…We selected MBP as a fusion tag after a few other tags were tested. We did not remove a MBP portion because it exhibited no phosphatase activity and was unexpected to disturb the phosphatase assay (Kashiwaba et al 2003;Komaki et al 2003). This is the case for many MBP fusions (Sachdev and Chirgwin 2000).…”

Chromatin Immunoprecipitation-Based Screen To Identify Functional Genomic Binding Sites for Sequence-Specific Transactivators

“…The exact role of PPM1J in human cells is not known, but its gene is conserved in mice and rats, and the murine homolog, PP2CZ, can associate with the ubiquitin-conjugating enzyme 9 (Ubc9). Ubc9 is involved in the sumoylation of protein substrates, and the PP2CZ-Ubc9 interaction is enhanced in the presence of the small ubiquitin-related modifier (SUMO) protein (38). These observations suggest that PPM1J may be involved in the regulation of sumoylation processes in the cell.…”