scholarly journals Protein kinase D1 phosphorylation of KAT7 enhances its protein stability and promotes replication licensing and cell proliferation

2020 ◽  
Vol 6 (1) ◽  
Author(s):  
Yao Liang ◽  
Yuanyuan Su ◽  
Chenzhong Xu ◽  
Na Zhang ◽  
Doudou Liu ◽  
...  

Abstract The histone acetyltransferase (HAT) KAT7/HBO1/MYST2 plays a crucial role in the pre-replication complex (pre-RC) formation, DNA replication and cell proliferation via acetylation of histone H4 and H3. In a search for protein kinase D1 (PKD1)-interacting proteins, we have identified KAT7 as a potential PKD1 substrate. We show that PKD1 directly interacts and phosphorylates KAT7 at Thr97 and Thr331 in vitro and in vivo. PKD1-mediated phosphorylation of KAT7 enhances its expression levels and stability by reducing its ubiquitination-mediated degradation. Significantly, the phospho-defective mutant KAT7-Thr97/331A attenuates histone H4 acetylation levels, MCM2/6 loading on the chromatin, DNA replication and cell proliferation. Similarly, PKD1 knockdown decreases, whereas the constitutive active mutant PKD1-CA increases histone H4 acetylation levels and MCM2/6 loading on the chromatin. Overall, these results suggest that PKD1-mediated phosphorylation of KAT7 may be required for pre-RC formation and DNA replication.

2020 ◽  
Vol 22 (Supplement_2) ◽  
pp. ii19-ii19
Author(s):  
Anca Mihalas ◽  
Heather Feldman ◽  
Anoop Patel ◽  
Patrick Paddison

Abstract Current standard of care therapy for glioblastoma (GBM) includes cytoreduction followed by ablative therapies that target rapidly dividing cell types. However, the presence of quiescent-like/G0 states, therefore, represents a natural reservoir of tumor cells that are resistant to current treatments. Quiescence or G0 phase is a reversible state of “stasis” cells enter in response to developmental or environmental cues. To gain insight into how glioblastoma cells might regulate G0-like states, we performed a genome-wide CRISPR-Cas9 screen in patient-derived GBM stem-like cells (GSCs) harboring a G0-reporter to identify genes that when inhibited trap GSCs in G0-like states. Among the top screen hits were members of the Tip60/KAT5 histone acetyltransferase complex, which targets both histones (e.g., H4) and non-histone proteins for acetylation. NuA4 functions as a transcriptional activator, whose activities are coordinated with MYC in certain contexts, and also participates in DNA double-strand break repair by facilitating chromatin opening. However, currently little is known about the roles for NuA4 complex in GBM biology. Through modeling KAT5 function in GSC in vitro cultures and in vivo tumors, we find that KAT5 inhibition causes cells to arrest in a G0-like state with high p27 levels, G1-phase DNA content, low protein synthesis rates, low rRNA rates, lower metabolic rate, suppression of cell cycle gene expression, and low histone H4 acetylation. Interestingly, partial inhibition of KAT5 activity slows highly aggressive tumor growth, while increasing p27hi H4-aclow populations. Remarkably, we that low grade gliomas have significantly higher H4-aclow subpopulations and generally lower H4-ac levels than aggressive grade IV tumors. Taken together, our results suggest that NuA4/KAT5 activity may play a key role in quiescence ingress/egress in glioma and that targeting its activity in high grade tumors may effectively “down grade” them, thus, increase patient survival.


2004 ◽  
Vol 24 (21) ◽  
pp. 9568-9579 ◽  
Author(s):  
Yanjiao Zhou ◽  
Teresa S.-F. Wang

ABSTRACT DNA replication depends critically upon chromatin structure. Little is known about how the replication complex overcomes the nucleosome packages in chromatin during DNA replication. To address this question, we investigate factors that interact in vivo with the principal initiation DNA polymerase, DNA polymerase α (Polα). The catalytic subunit of budding yeast Polα (Pol1p) has been shown to associate in vitro with the Spt16p-Pob3p complex, a component of the nucleosome reorganization system required for both replication and transcription, and with a sister chromatid cohesion factor, Ctf4p. Here, we show that an N-terminal region of Polα (Pol1p) that is evolutionarily conserved among different species interacts with Spt16p-Pob3p and Ctf4p in vivo. A mutation in a glycine residue in this N-terminal region of POL1 compromises the ability of Pol1p to associate with Spt16p and alters the temporal ordered association of Ctf4p with Pol1p. The compromised association between the chromatin-reorganizing factor Spt16p and the initiating DNA polymerase Pol1p delays the Pol1p assembling onto and disassembling from the late-replicating origins and causes a slowdown of S-phase progression. Our results thus suggest that a coordinated temporal and spatial interplay between the conserved N-terminal region of the Polα protein and factors that are involved in reorganization of nucleosomes and promoting establishment of sister chromatin cohesion is required to facilitate S-phase progression.


2011 ◽  
Vol 18 (5) ◽  
pp. 243-252 ◽  
Author(s):  
Federica Franciosi ◽  
Valentina Lodde ◽  
Ghylène Goudet ◽  
Guy Duchamp ◽  
Stefan Deleuze ◽  
...  

2001 ◽  
Vol 88 (3) ◽  
pp. 319-324 ◽  
Author(s):  
Ciro Indolfi ◽  
Eugenio Stabile ◽  
Carmela Coppola ◽  
Adriana Gallo ◽  
Cinzia Perrino ◽  
...  

Reproduction ◽  
2020 ◽  
Vol 159 (1) ◽  
pp. 1-13 ◽  
Author(s):  
Wei Cui ◽  
Agnes Cheong ◽  
Yongsheng Wang ◽  
Yuran Tsuchida ◽  
Yong Liu ◽  
...  

Microspherule protein 1 (MCRS1, also known as MSP58) is an evolutionarily conserved protein that has been implicated in various biological processes. Although a variety of functions have been attributed to MCRS1 in vitro, mammalian MCRS1 has not been studied in vivo. Here we report that MCRS1 is essential during early murine development. Mcrs1 mutant embryos exhibit normal morphology at the blastocyst stage but cannot be recovered at gastrulation, suggesting an implantation failure. Outgrowth (OG) assays reveal that mutant blastocysts do not form a typical inner cell mass (ICM) colony, the source of embryonic stem cells (ESCs). Surprisingly, cell death and histone H4 acetylation analysis reveal that apoptosis and global H4 acetylation are normal in mutant blastocysts. However, analysis of lineage specification reveals that while the trophoblast and primitive endoderm are properly specified, the epiblast lineage is compromised and exhibits a severe reduction in cell number. In summary, our study demonstrates the indispensable role of MCRS1 in epiblast development during early mammalian embryogenesis.


2012 ◽  
Vol 303 (3) ◽  
pp. G356-G366 ◽  
Author(s):  
Steven H. Young ◽  
Nora Rozengurt ◽  
James Sinnett-Smith ◽  
Enrique Rozengurt

We have examined the role of protein kinase D1 (PKD1) signaling in intestinal epithelial cell migration. Wounding monolayer cultures of intestinal epithelial cell line IEC-18 or IEC-6 induced rapid PKD1 activation in the cells immediately adjacent to the wound edge, as judged by immunofluorescence microscopy with an antibody that detects the phosphorylated state of PKD1 at Ser916, an autophosphorylation site. An increase in PKD1 phosphorylation at Ser916 was evident as early as 45 s after wounding, reached a maximum after 3 min, and persisted for ≥15 min. PKD1 autophosphorylation at Ser916 was prevented by the PKD family inhibitors kb NB 142-70 and CRT0066101. A kb NB 142-70-sensitive increase in PKD autophosphorylation was also elicited by wounding IEC-6 cells. Using in vitro kinase assays after PKD1 immunoprecipitation, we corroborated that wounding IEC-18 cells induced rapid PKD1 catalytic activation. Further results indicate that PKD1 signaling is required to promote migration of intestinal epithelial cells into the denuded area of the wound. Specifically, treatment with kb NB 142-70 or small interfering RNAs targeting PKD1 markedly reduced wound-induced migration in IEC-18 cells. To test whether PKD1 promotes migration of intestinal epithelial cells in vivo, we used transgenic mice that express elevated PKD1 protein in the small intestinal epithelium. Enterocyte migration was markedly increased in the PKD1 transgenic mice. These results demonstrate that PKD1 activation is one of the early events initiated by wounding a monolayer of intestinal epithelial cells and indicate that PKD1 signaling promotes the migration of these cells in vitro and in vivo.


2009 ◽  
Vol 29 (20) ◽  
pp. 5455-5464 ◽  
Author(s):  
Kira Glover-Cutter ◽  
Stéphane Larochelle ◽  
Benjamin Erickson ◽  
Chao Zhang ◽  
Kevan Shokat ◽  
...  

ABSTRACT The function of human TFIIH-associated Cdk7 in RNA polymerase II (Pol II) transcription and C-terminal domain (CTD) phosphorylation was investigated in analogue-sensitive Cdk7 as/as mutant cells where the kinase can be inhibited without disrupting TFIIH. We show that both Cdk7 and Cdk9/PTEFb contribute to phosphorylation of Pol II CTD Ser5 residues on transcribed genes. Cdk7 is also a major kinase of CTD Ser7 on Pol II at the c-fos and U snRNA genes. Furthermore, TFIIH and recombinant Cdk7-CycH-Mat1 as well as recombinant Cdk9-CycT1 phosphorylated CTD Ser7 and Ser5 residues in vitro. Inhibition of Cdk7 in vivo suppressed the amount of Pol II accumulated at 5′ ends on several genes including c-myc, p21, and glyceraldehyde-3-phosphate dehydrogenase genes, indicating reduced promoter-proximal pausing or polymerase “leaking” into the gene. Consistent with a 5′ pausing defect, Cdk7 inhibition reduced recruitment of the negative elongation factor NELF at start sites. A role of Cdk7 in regulating elongation is further suggested by enhanced histone H4 acetylation and diminished histone H4 trimethylation on lysine 36—two marks of elongation—within genes when the kinase was inhibited. Consistent with a new role for TFIIH at 3′ ends, it was detected within genes and 3′-flanking regions, and Cdk7 inhibition delayed pausing and transcription termination.


2007 ◽  
Vol 28 (1) ◽  
pp. 140-153 ◽  
Author(s):  
Masayoshi Iizuka ◽  
Olga F. Sarmento ◽  
Takao Sekiya ◽  
Heidi Scrable ◽  
C. David Allis ◽  
...  

ABSTRACT Hbo1 is a histone acetyltransferase (HAT) that is required for global histone H4 acetylation, steroid-dependent transcription, and chromatin loading of MCM2-7 during DNA replication licensing. It is the catalytic subunit of protein complexes that include ING and JADE proteins, growth regulatory factors and candidate tumor suppressors. These complexes are thought to act via tumor suppressor p53, but the molecular mechanisms and links between stress signaling and chromatin, are currently unknown. Here, we show that p53 physically interacts with Hbo1 and negatively regulates its HAT activity in vitro and in cells. Two physiological stresses that stabilize p53, hyperosmotic shock and DNA replication fork arrest, also inhibit Hbo1 HAT activity in a p53-dependent manner. Hyperosmotic stress during G1 phase specifically inhibits the loading of the MCM2-7 complex, providing an example of the chromatin output of this pathway. These results reveal a direct regulatory connection between p53-responsive stress signaling and Hbo1-dependent chromatin pathways.


2005 ◽  
Vol 25 (9) ◽  
pp. 3814-3830 ◽  
Author(s):  
Laurent Miccoli ◽  
Isabelle Frouin ◽  
Olivia Novac ◽  
Domenic Di Paola ◽  
Francis Harper ◽  
...  

ABSTRACT The human stress-activated protein kin17 accumulates in the nuclei of proliferating cells with predominant colocalization with sites of active DNA replication. The distribution of kin17 protein is in equilibrium between chromatin-DNA and the nuclear matrix. An increased association with nonchromatin nuclear structure is observed in S-phase cells. We demonstrated here that kin17 protein strongly associates in vivo with DNA fragments containing replication origins in both human HeLa and monkey CV-1 cells. This association was 10-fold higher than that observed with nonorigin control DNA fragments in exponentially growing cells. In addition, the association of kin17 protein to DNA fragments containing replication origins was also analyzed as a function of the cell cycle. High binding of kin17 protein was found at the G1/S border and throughout the S phase and was negligible in both G0 and M phases. Specific monoclonal antibodies against kin17 protein induced a threefold inhibition of in vitro DNA replication of a plasmid containing a minimal replication origin that could be partially restored by the addition of recombinant kin17 protein. Immunoelectron microscopy confirmed the colocalization of kin17 protein with replication proteins like RPA, PCNA, and DNA polymerase α. A two-step chromatographic fractionation of nuclear extracts from HeLa cells revealed that kin17 protein localized in vivo in distinct protein complexes of high molecular weight. We found that kin17 protein purified within an ∼600-kDa protein complex able to support in vitro DNA replication by means of two different biochemical methods designed to isolate replication complexes. In addition, the reduced in vitro DNA replication activity of the multiprotein replication complex after immunodepletion for kin17 protein highlighted for a direct role in DNA replication at the origins.


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