Sumoylation of the net inhibitory domain (NID) is stimulated by PIAS1 and has a negative effect on the transcriptional activity of Net

Abstract

Net (Elk-3, Sap-2, Erp) and the related ternary complex factors Elk-1 and Sap-1 are effectors of multiple signalling pathways at the transcriptional level and play a key role in the dynamic regulation of gene expression. Net is distinct from Elk-1 and Sap-1, in that it is a strong repressor of transcription that is converted to an activator by the Ras/Erk signalling pathway. Two autonomous repression domains of Net, the NID and the CID, mediate repression. We have previously shown that the corepressor CtBP is implicated in repression by the CID. In this report we show that repression by the NID involves a different pathway, sumoylation by Ubc9 and PIAS1. PIAS1 interacts with the NID in the two-hybrid assay and in vitro. Ubc9 and PIAS1 stimulate sumoylation in vivo of lysine 162 in the NID. Sumoylation of lysine 162 increases repression by Net and decreases the positive activity of Net. These results increase our understanding of how one of the ternary complex factors regulates transcription, and contribute to the understanding of how different domains of a transcription factor participate in the complexity of regulation of gene expression.

The expression of ELK transcription factors in adult DRG: Novel isoforms, antisense transcripts and upregulation by nerve damage

“…4A). The bands of ~14 and ~50 kDa are consistent, respectively, with the size of protein detected in COS-7 cells transfected with an Elk3d expression vector (data not shown) and with full-length Elk3 (Giovane et al, 1997), while the larger bands may correspond to the sumoylated conjugates of Elk3 detected in COS-7 cells transfected with both Elk3 and SUMO-1 cDNAs (Wasylyk et al, 2005). In adult heart, an additional band of ~29 kDa of unknown identity was also detected (Fig.…”

Regulation of the Ets-1 transcription factor by sumoylation and ubiquitinylation

“…Our data reveal that Ets-1 indeed undergoes SUMO modifications, with Ubc9 being able to enhance sumoylation of Ets-1. We also examined whether PIAS proteins can act as E3 ligases for SUMO modification of Ets-1, since these proteins can enhance SUMO conjugation of many transcription factors, including ETS transcription factors, such as Elk-1 (Yang and Sharrocks, 2005) and Net (Wasylyk et al, 2005). Our data show that PIASy is able to interact and to enhance sumoylation of Ets-1.…”

“…SUMO modification appears to play a role in a variety of cellular processes including protein-protein interaction, subcellular localization, protein stabilization and transcriptional regulation (Dohmen, 2004). A large number of SUMO target proteins have been identified, including several members of the Ets transcription factors family (Chakrabarti et al, 2000;Yang et al, 2003;Degerny et al, 2005;Leight et al, 2005;van den Akker et al, 2005;Wasylyk et al, 2005). Recently, we reported that the ERM Ets protein is sumoylated and that sumoylation of ERM represses its transcriptional activity (Degerny et al, 2005).…”

The Ternary Complex Factor Net Regulates Cell Migration through Inhibition of PAI-1 Expression

“…The CID interacts with the corepressor E1A C-terminal binding protein, which represses transcription through histone deacetylase activity. The NID interacts with the sumoylation E2 and E3 enzymes Ubc9 and PIAS1, and NID sumoylation on lysine 162 increases repression by Net (62). Interestingly, sumoylation of Elk-1 leads to recruitment of the histone deacetylase HDAC2 and transcriptional repression (66).…”