SUMOylation regulates the nuclear mobility of CREB binding protein and its association with nuclear bodies in live cells

Abstract

The lysine acetyltransferase CREB binding protein (CBP) is required for chromatin modification and transcription at many gene promoters. In fixed cells, a large proportion of CBP colocalises to PML or nuclear bodies. Using live cell imaging, we show here that YFP-tagged CBP expressed in HEK293 cells undergoes gradual accumulation in nuclear bodies, some of which are mobile and migrate towards the nuclear envelope. Deletion of a short lysine-rich domain that contains the major SUMO acceptor sites of CBP abrogated its ability to be SUMO modified, and prevented its association with endogenous SUMO-1/PML speckles in vivo. This SUMO-defective CBP showed enhanced ability to co-activate AML1-mediated transcription. Deletion mapping revealed that the SUMO-modified region was not sufficient for targeting CBP to PML bodies, as C-terminally truncated mutants containing this domain showed a strong reduction in accumulation at PML bodies. Fluorescence recovery after photo-bleaching (FRAP) experiments revealed that YFP–CBPΔ998–1087 had a retarded recovery time in the nucleus, as compared to YFP–CBP. These results indicate that SUMOylation regulates CBP function by influencing its shuttling between nuclear bodies and chromatin microenvironments.

Nuclear translocation of DJ-1 during oxidative stress-induced neuronal cell death

“…Second, DJ-1 may directly modulate the activity of CBP. The activity of CBP is regulated by posttranslational modification, including sumoylation [70]. Because DJ-1 may inhibit protein sumoylation [18], sumoylation of p300/CBP may be inhibited by nuclear DJ-1.…”

Hypoxia-mediated alterations and their role in the HER-2/neuregulated CREB status and localization

“…These results are in contrast to those reported by Nakayama [20] and might be explained by differences in the cell systems analysed. Furthermore, SUMOylation has been shown to regulate the activity and function of CREB under physiologic conditions [14–16]. These data were extended in this study to hypoxia-induced CREB SUMOylation, but its role during hypoxia requires further investigation.…”

SNP-SIG 2013: from coding to non-coding - new approaches for genomic variant interpretation

“…Literature-verified SUMOylation of the 19 potential SUMO-1 targeting TFs are presented in Table 6. The top five potential SUMO TFs, ELK-1 [30], E2F [31], NFY [32], and CREB [33], have all been confirmed to be SUMO substrates by literature review and the percentage of SUMO-verified TFs shown in Figure 6 indicates that the most favorable result is obtained when using the M*C*T combination.…”