scholarly journals Biochemical and functional characterization of a meiosis-specific Pch2/ORC AAA+ assembly

2020 ◽  
Vol 3 (11) ◽  
pp. e201900630
Author(s):  
María Ascensión Villar-Fernández ◽  
Richard Cardoso da Silva ◽  
Magdalena Firlej ◽  
Dongqing Pan ◽  
Elisabeth Weir ◽  
...  
Keyword(s):  
Biochemical Analysis ◽  
Budding Yeast ◽  
Functional Characterization ◽  
Efficient Removal ◽  
Terminal Domain ◽  
Origins Of Replication ◽  
Mcm Helicase ◽  
A Subunit ◽  
Aaa Protein

Pch2 is a meiosis-specific AAA+ protein that controls several important chromosomal processes. We previously demonstrated that Orc1, a subunit of the ORC, functionally interacts with budding yeast Pch2. The ORC (Orc1-6) AAA+ complex loads the AAA+ MCM helicase to origins of replication, but whether and how ORC collaborates with Pch2 remains unclear. Here, we show that a Pch2 hexamer directly associates with ORC during the meiotic G2/prophase. Biochemical analysis suggests that Pch2 uses its non-enzymatic NH2-terminal domain and AAA+ core and likely engages the interface of ORC that also binds to Cdc6, a factor crucial for ORC-MCM binding. Canonical ORC function requires association with origins, but we show here that despite causing efficient removal of Orc1 from origins, nuclear depletion of Orc2 and Orc5 does not trigger Pch2/Orc1-like meiotic phenotypes. This suggests that the function for Orc1/Pch2 in meiosis can be executed without efficient association of ORC with origins of replication. In conclusion, we uncover distinct functionalities for Orc1/ORC that drive the establishment of a non-canonical, meiosis-specific AAA+ assembly with Pch2.

scholarly journals A meiosis-specific AAA+ assembly reveals repurposing of ORC during budding yeast gametogenesis

2019 ◽  
Author(s):  
María Ascensión Villar-Fernández ◽  
Richard Cardoso da Silva ◽  
Dongqing Pan ◽  
Elisabeth Weir ◽  
Annika Sarembe ◽  
...  
Keyword(s):  
Biochemical Analysis ◽  
Budding Yeast ◽  
Replication Origins ◽  
Terminal Domain ◽  
Binding Interface ◽  
Mcm Helicase ◽  
A Subunit ◽  
Per Se ◽  
Aaa Protein

ABSTRACTORC (Orc1-6) is an AAA+ complex that loads the AAA+ MCM helicase to replication origins. Orc1, a subunit of ORC, functionally interacts with budding yeast Pch2, a meiosis-specific AAA+ protein. Pch2 regulates several chromosomal events of gametogenesis, but mechanisms that dictate Pch2 function remain poorly understood. We demonstrate that ORC directly interacts with an AAA+ Pch2 hexamer. The ORC-Pch2 assembly is established without Cdc6, a factor crucial for ORC-MCM binding. Biochemical analysis suggests that Pch2 utilizes ORC’s Cdc6-binding interface and employs its non-enzymatic NH2-terminal domain and AAA+ core to engage ORC. In contrast to phenotypes observed upon Orc1 impairment, nuclear depletion of other subunits of ORC does not lead to Pch2-like phenotypes, indicating that ORC integrity per se is not required to support Pch2 function. We thus reveal functional interplay between Pch2 and ORC, and uncover the repurposing of ORC to establish a non-canonical and meiosis-specific AAA+ assembly.

scholarly journals Functional Characterization of the C-terminal Domain of the CytochromecMaturation Protein CcmE

2005 ◽  
Vol 280 (44) ◽  
pp. 36747-36753 ◽  
Author(s):  
Edgar M. Harvat ◽  
Julie M. Stevens ◽  
Christina Redfield ◽  
Stuart J. Ferguson
Keyword(s):  
Functional Characterization ◽  
Terminal Domain

scholarly journals Cloning and functional characterization of a subunit of the transporter associated with antigen processing

1997 ◽  
Vol 94 (16) ◽  
pp. 8708-8713 ◽  
Author(s):  
S. Li ◽  
H.-O. Sjogren ◽  
U. Hellman ◽  
R. F. Pettersson ◽  
P. Wang
Keyword(s):  
Antigen Processing ◽  
Functional Characterization ◽  
A Subunit

scholarly journals The rare sugar N-acetylated viosamine is a major component of Mimivirus fibers

2017 ◽  
Vol 292 (18) ◽  
pp. 7385-7394 ◽  
Author(s):  
Francesco Piacente ◽  
Cristina De Castro ◽  
Sandra Jeudy ◽  
Matteo Gaglianone ◽  
Maria Elena Laugieri ◽  
...  
Keyword(s):  
Structural Model ◽  
Functional Characterization ◽  
Virus Genome ◽  
Amino Group ◽  
Rare Sugar ◽  
Functional Annotations ◽  
Terminal Domain ◽  
Icosahedral Capsid

The giant virus Mimivirus encodes an autonomous glycosylation system that is thought to be responsible for the formation of complex and unusual glycans composing the fibers surrounding its icosahedral capsid, including the dideoxyhexose viosamine. Previous studies have identified a gene cluster in the virus genome, encoding enzymes involved in nucleotide-sugar production and glycan formation, but the functional characterization of these enzymes and the full identification of the glycans found in viral fibers remain incomplete. Because viosamine is typically found in acylated forms, we suspected that one of the genes might encode an acyltransferase, providing directions to our functional annotations. Bioinformatic analyses indicated that the L142 protein contains an N-terminal acyltransferase domain and a predicted C-terminal glycosyltransferase. Sequence analysis of the structural model of the L142 N-terminal domain indicated significant homology with some characterized sugar acetyltransferases that modify the C-4 amino group in the bacillosamine or perosamine biosynthetic pathways. Using mass spectrometry and NMR analyses, we confirmed that the L142 N-terminal domain is a sugar acetyltransferase, catalyzing the transfer of an acetyl moiety from acetyl-CoA to the C-4 amino group of UDP-d-viosamine. The presence of acetylated viosamine in vivo has also been confirmed on the glycosylated viral fibers, using GC-MS and NMR. This study represents the first report of a virally encoded sugar acetyltransferase.

scholarly journals Defining the human C2H2 zinc finger degrome targeted by thalidomide analogs through CRBN

Science ◽  
2018 ◽  
Vol 362 (6414) ◽  
pp. eaat0572 ◽  
Author(s):  
Quinlan L. Sievers ◽  
Georg Petzold ◽  
Richard D. Bunker ◽  
Aline Renneville ◽  
Mikołaj Słabicki ◽  
...  
Keyword(s):  
Transcription Factors ◽  
Small Molecules ◽  
Zinc Finger ◽  
Ubiquitin Ligase ◽  
Biochemical Analysis ◽  
Zinc Fingers ◽  
Functional Characterization ◽  
C2h2 Zinc Finger

The small molecules thalidomide, lenalidomide, and pomalidomide induce the ubiquitination and proteasomal degradation of the transcription factors Ikaros (IKZF1) and Aiolos (IKZF3) by recruiting a Cys2-His2 (C2H2) zinc finger domain to Cereblon (CRBN), the substrate receptor of the CRL4CRBN E3 ubiquitin ligase. We screened the human C2H2 zinc finger proteome for degradation in the presence of thalidomide analogs, identifying 11 zinc finger degrons. Structural and functional characterization of the C2H2 zinc finger degrons demonstrates how diverse zinc finger domains bind the permissive drug-CRBN interface. Computational zinc finger docking and biochemical analysis predict that more than 150 zinc fingers bind the drug-CRBN complex in vitro, and we show that selective zinc finger degradation can be achieved through compound modifications. Our results provide a rationale for therapeutically targeting transcription factors that were previously considered undruggable.

Structural and functional characterization of the N-terminal domain of the yeast Mg2+channel Mrs2

2013 ◽  
Vol 69 (9) ◽  
pp. 1653-1664 ◽  
Author(s):  
Muhammad Bashir Khan ◽  
Gerhard Sponder ◽  
Björn Sjöblom ◽  
Soňa Svidová ◽  
Rudolf J. Schweyen ◽  
...  
Keyword(s):  
Functional Characterization ◽  
Terminal Domain

scholarly journals Functional characterization of heat-shock protein 90 fromOryza sativaand crystal structure of its N-terminal domain

2015 ◽  
Vol 71 (6) ◽  
pp. 688-696 ◽  
Author(s):  
Swetha Raman ◽  
Kaza Suguna
Keyword(s):  
Crystal Structure ◽  
Heat Shock ◽  
Heat Shock Protein ◽  
Biochemical Characterization ◽  
Functional Characterization ◽  
Cell Signalling ◽  
Physiological Role ◽  
Heat Shock Protein 90 ◽  
Terminal Domain

Heat-shock protein 90 (Hsp90) is an ATP-dependent molecular chaperone that is essential for the normal functioning of eukaryotic cells. It plays crucial roles in cell signalling, cell-cycle control and in maintaining proteome integrity and protein homeostasis. In plants, Hsp90s are required for normal plant growth and development. Hsp90s are observed to be upregulated in response to various abiotic and biotic stresses and are also involved in immune responses in plants. Although there are several studies elucidating the physiological role of Hsp90s in plants, their molecular mechanism of action is still unclear. In this study, biochemical characterization of an Hsp90 protein from rice (Oryza sativa; OsHsp90) has been performed and the crystal structure of its N-terminal domain (OsHsp90-NTD) was determined. The binding of OsHsp90 to its substrate ATP and the inhibitor 17-AAG was studied by fluorescence spectroscopy. The protein also exhibited a weak ATPase activity. The crystal structure of OsHsp90-NTD was solved in complex with the nonhydrolyzable ATP analogue AMPPCP at 3.1 Å resolution. The domain was crystallized by cross-seeding with crystals of the N-terminal domain of Hsp90 fromDictyostelium discoideum, which shares 70% sequence identity with OsHsp90-NTD. This is the second reported structure of a domain of Hsp90 from a plant source.

scholarly journals Genetic and Biochemical Characterization of the Yeast Spo12 Protein

1999 ◽  
Vol 10 (11) ◽  
pp. 3689-3703 ◽  
Author(s):  
Megan E. Grether ◽  
Ira Herskowitz
Keyword(s):  
Biochemical Analysis ◽  
Biochemical Characterization ◽  
Nuclear Division ◽  
Budding Yeast ◽  
Hybrid Analysis ◽  
Vegetative Cells ◽  
Synthetically Lethal ◽  
Cdc28 Kinase ◽  
Two Hybrid

We have performed a genetic and biochemical analysis of theSPO12 gene, which regulates meiotic nuclear divisions in budding yeast. When sporulated, spo12 mutants undergo a single meiotic nuclear division most closely resembling meiosis II. We observed that Spo12 protein is localized to the nucleus during both meiotic divisions and that Clb1-Cdc28, Clb3-Cdc28, Clb4-Cdc28, and Clb5-Cdc28 kinase activities during meiosis were not affected by a spo12 mutation. Using two-hybrid analysis, we identified several genes, three of which are meiotically induced, that may code for proteins that interact with Spo12p. We also observed that two genes, BNS1 (Bypasses Need for Spo12p), which has homology to SPO12, andSPO13, whose mutant phenotype is like that ofspo12, can partially suppress the meiotic defect ofspo12 mutants when overexpressed. We found that Spo12p is also localized to the nucleus in vegetative cells and that its level peaks during G2/M. We observed that a spo12 mutation is synthetically lethal in vegetative cells with a mutation inHCT1, a gene necessary for cells to exit mitosis, suggesting that Spo12p may have a role in exit from mitosis.

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