| First Author | Qin W | Year | 2021 |
| Journal | Nucleic Acids Res | Volume | 49 |
| Issue | 13 | Pages | 7406-7423 |
| PubMed ID | 34214177 | Mgi Jnum | J:307846 |
| Mgi Id | MGI:6726213 | Doi | 10.1093/nar/gkab548 |
| Citation | Qin W, et al. (2021) Phosphorylation of the HP1beta hinge region sequesters KAP1 in heterochromatin and promotes the exit from naive pluripotency. Nucleic Acids Res 49(13):7406-7423 |
| abstractText | Heterochromatin binding protein HP1beta plays an important role in chromatin organization and cell differentiation, however the underlying mechanisms remain unclear. Here, we generated HP1beta-/- embryonic stem cells and observed reduced heterochromatin clustering and impaired differentiation. We found that during stem cell differentiation, HP1beta is phosphorylated at serine 89 by CK2, which creates a binding site for the pluripotency regulator KAP1. This phosphorylation dependent sequestration of KAP1 in heterochromatin compartments causes a downregulation of pluripotency factors and triggers pluripotency exit. Accordingly, HP1beta-/- and phospho-mutant cells exhibited impaired differentiation, while ubiquitination-deficient KAP1-/- cells had the opposite phenotype with enhanced differentiation. These results suggest that KAP1 regulates pluripotency via its ubiquitination activity. We propose that the formation of subnuclear membraneless heterochromatin compartments may serve as a dynamic reservoir to trap or release cellular factors. The sequestration of essential regulators defines a novel and active role of heterochromatin in gene regulation and represents a dynamic mode of remote control to regulate cellular processes like cell fate decisions. |
