Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.6.1.3 (ATPase)
65,361 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

DNA repair is regulated on many levels by ubiquitination. In order to identify novel connections between DNA repair pathways and ubiquitin signaling, we used mass spectrometry to identify proteins that interact with lysine 6-linked polyubiquitin chains. From this proteomic screen, we identified the DNA repair protein WRNIP1 (Werner helicase-interacting protein 1), along with nucleosome assembly protein 1, as novel ubiquitin-interacting proteins. We found that a small zinc finger domain at the N terminus of WRNIP1 is sufficient and necessary for noncovalent ubiquitin binding. This ubiquitin-binding zinc finger (UBZ) domain binds polyubiquitin but not monoubiquitin and appears to show no specificity for polyubiquitin chain linkage. A homologous zinc finger domain in RAD18 also binds polyubiquitin, suggesting a wider role for the UBZ domain in DNA repair. The WRNIP1 ubiquitin-binding function, along with its previously established ATPase activity, suggests that WRNIP1 plays a role in the metabolism of ubiquitinated proteins. Supporting this model, deletion of MGS1, the yeast homolog of WRNIP1, slows the rate of ubiquitin turnover, rendering yeast resistant to cycloheximide. We also find that WRNIP1 is heavily modified with ubiquitin and SUMO, revealing complex layers in the involvement of ubiquitin pathway proteins in the regulation of DNA repair. The novel ubiquitin-binding ability of WRNIP1 sheds light on the role of UBZ domain-containing proteins in postreplication DNA repair.
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PMID:Werner helicase-interacting protein 1 binds polyubiquitin via its zinc finger domain. 1755 Aug 99

ATRX (alpha thalassemia/mental retardation syndrome X-linked) belongs to the SWI2/SNF2 family of chromatin remodeling proteins. Besides the ATPase/helicase domain at its C terminus, it contains a PHD-like zinc finger at the N terminus. Mutations in the ATRX gene are associated with X-linked mental retardation (XLMR) often accompanied by alpha thalassemia (ATRX syndrome). Although ATRX has been postulated to be a transcriptional regulator, its precise roles remain undefined. We demonstrate ATRX localization at the telomeres in interphase mouse embryonic stem (ES) cells in synchrony with the incorporation of H3.3 during telomere replication at S phase. Moreover, we found that chromobox homolog 5 (CBX5) (also known as heterochromatin protein 1 alpha, or HP1 alpha) is also present at the telomeres in ES cells. We show by coimmunoprecipitation that this localization is dependent on the association of ATRX with histone H3.3, and that mutating the K4 residue of H3.3 significantly diminishes ATRX and H3.3 interaction. RNAi-knockdown of ATRX induces a telomere-dysfunction phenotype and significantly reduces CBX5 enrichment at the telomeres. These findings suggest a novel function of ATRX, working in conjunction with H3.3 and CBX5, as a key regulator of ES-cell telomere chromatin.
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PMID:ATRX interacts with H3.3 in maintaining telomere structural integrity in pluripotent embryonic stem cells. 2011 May 66

The initiation of DNA replication starts from origins and is controlled by a multiprotein complex, which involves about twenty protein factors. One of the important factors is hetrohexameric minichromosome maintenance (MCM2-7) protein complex which is evolutionary conserved and functions as essential replicative helicase for DNA replication. Here we report the isolation and characterization of a single subunit of pea MCM protein complex, the MCM6. The deduced amino acid (827) sequence contains all the known canonical MCM motifs including zinc finger, MCM specific Walker A and Walker B and arginine finger. The purified recombinant protein contains ATP-dependent 3'-5' DNA helicase, ATP-binding and ATPase activities. The helicase activity was stimulated by replication fork like substrate and anti-MCM6 antibodies curtail all the enzyme activities of MCM6 protein. In vitro it self-interacts and forms a homohexamer which is active for DNA helicase and ATPase activities. The complete protein is required for self-interaction as the truncated MCM6 proteins were unable to self-interact. Western blot analysis and in vivo immunostaining followed by confocal microscopy showed the localization of MCM6 both in the nucleus and cytosol. These findings provide first direct evidence that single subunit MCM6 contains DNA helicase activity which is unique to plant MCM6 protein, as this activity was only reported for heteromultimers of MCM proteins in animal system. This discovery should make an important contribution to a better understanding of DNA replication in plants.
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PMID:A single subunit MCM6 from pea forms homohexamer and functions as DNA helicase. 2073 May 96

The AAA (ATPase-associated with various cellular activities) ATPase p97 acts on diverse substrate proteins to partake in various cellular processes such as membrane fusion and endoplasmic reticulum-associated degradation (ERAD). In membrane fusion, p97 is thought to function in analogy to the related ATPase NSF (N-ethylmaleimide-sensitive fusion protein), which promotes membrane fusion by disassembling a SNARE complex. In ERAD, p97 dislocates misfolded proteins from the ER membrane to facilitate their turnover by the proteasome. Here, we identify a novel function of p97 in endocytic trafficking by establishing the early endosomal autoantigen 1 (EEA1) as a new p97 substrate. We demonstrate that a fraction of p97 is localized to the early endosome membrane, where it binds EEA1 via the N-terminal C2H2 zinc finger domain. Inhibition of p97 either by siRNA or a pharmacological inhibitor results in clustering and enlargement of early endosomes, which is associated with an altered trafficking pattern for an endocytic cargo. Mechanistically, we show that p97 inhibition causes increased EEA1 self-association at the endosome membrane. We propose that p97 may regulate the size of early endosomes by governing the oligomeric state of EEA1.
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PMID:The p97 ATPase associates with EEA1 to regulate the size of early endosomes. 2155 36

WRNIP1 (Werner helicase-interacting protein 1) was originally identified as a protein that interacts with the Werner syndrome responsible gene product. WRNIP1 contains a ubiquitin-binding zinc-finger (UBZ) domain in the N-terminal region and two leucine zipper motifs in the C-terminal region. In addition, it possesses an ATPase domain in the middle of the molecule and the lysine residues serving as ubiquitin acceptors in the entire of the molecule. Here, we report that WRNIP1 accumulates in laser light irradiated sites very rapidly via its ubiquitin-binding zinc finger domain, which is known to bind polyubiquitin and to be involved in ubiquitination of WRNIP1 itself. The accumulation of WRNIP1 in laser light irradiated sites also required the C-terminal region containing two leucine zippers, which is reportedly involved in the oligomerization of WRNIP1. Mutated WRNIP1 with a deleted ATPase domain or with mutations in lysine residues, which serve as ubiquitin acceptors, accumulated in laser light irradiated sites, suggesting that the ATPase domain of WRNIP1 and ubiquitination of WRNIP1 are dispensable for the accumulation.
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PMID:WRNIP1 accumulates at laser light irradiated sites rapidly via its ubiquitin-binding zinc finger domain and independently from its ATPase domain. 2220 48

The nuclear export of the preribosomal 60S (pre-60S) subunit is coordinated with late steps in ribosome assembly. Here, we show that Bud20, a conserved C(2)H(2)-type zinc finger protein, is an unrecognized shuttling factor required for the efficient export of pre-60S subunits. Bud20 associates with late pre-60S particles in the nucleoplasm and accompanies them into the cytoplasm, where it is released through the action of the Drg1 AAA-ATPase. Cytoplasmic Bud20 is then reimported via a Kap123-dependent pathway. The deletion of Bud20 induces a strong pre-60S export defect and causes synthetic lethality when combined with mutant alleles of known pre-60S subunit export factors. The function of Bud20 in ribosome export depends on a short conserved N-terminal sequence, as we observed that mutations or the deletion of this motif impaired 60S subunit export and generated the genetic link to other pre-60S export factors. We suggest that the shuttling Bud20 is recruited to the nascent 60S subunit via its central zinc finger rRNA binding domain to facilitate the subsequent nuclear export of the preribosome employing its N-terminal extension.
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PMID:The conserved Bud20 zinc finger protein is a new component of the ribosomal 60S subunit export machinery. 2304 92

Chromatin dynamics play a central role in maintaining genome integrity, but how this is achieved remains largely unknown. Here, we report that microrchidia CW-type zinc finger 2 (MORC2), an uncharacterized protein with a derived PHD finger domain and a conserved GHKL-type ATPase module, is a physiological substrate of p21-activated kinase 1 (PAK1), an important integrator of extracellular signals and nuclear processes. Following DNA damage, MORC2 is phosphorylated on serine 739 in a PAK1-dependent manner, and phosphorylated MORC2 regulates its DNA-dependent ATPase activity to facilitate chromatin remodeling. Moreover, MORC2 associates with chromatin and promotes gamma-H2AX induction in a PAK1 phosphorylation-dependent manner. Consequently, cells expressing MORC2-S739A mutation displayed a reduction in DNA repair efficiency and were hypersensitive to DNA-damaging agent. These findings suggest that the PAK1-MORC2 axis is critical for orchestrating the interplay between chromatin dynamics and the maintenance of genomic integrity through sequentially integrating multiple essential enzymatic processes.
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PMID:MORC2 signaling integrates phosphorylation-dependent, ATPase-coupled chromatin remodeling during the DNA damage response. 2326 Jun 67

Regulated protein degradation mediated by the ubiquitin-proteasome system (UPS) is critical to eukaryotic protein homeostasis. Often vital to degradation of protein substrates is their disassembly, unfolding, or extraction from membranes. These processes are catalyzed by the conserved AAA-ATPase Cdc48 (also known as p97). Here we characterize the Cuz1 protein (Cdc48-associated UBL/zinc finger protein-1), encoded by a previously uncharacterized arsenite-inducible gene in budding yeast. Cuz1, like its human ortholog ZFAND1, has both an AN1-type zinc finger (Zf_AN1) and a divergent ubiquitin-like domain (UBL). We show that Cuz1 modulates Cdc48 function in the UPS. The two proteins directly interact, and the Cuz1 UBL, but not Zf_AN1, is necessary for binding to the Cdc48 N-terminal domain. Cuz1 also associates, albeit more weakly, with the proteasome, and the UBL is dispensable for this interaction. Cuz1-proteasome interaction is strongly enhanced by exposure of cells to the environmental toxin arsenite, and in a proteasome mutant, loss of Cuz1 enhances arsenite sensitivity. Whereas loss of Cuz1 alone causes only minor UPS degradation defects, its combination with mutations in the Cdc48(Npl4-Ufd1) complex leads to much greater impairment. Cuz1 helps limit the accumulation of ubiquitin conjugates on both the proteasome and Cdc48, suggesting a possible role in the transfer of ubiquitylated substrates from Cdc48 to the proteasome or in their release from these complexes.
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PMID:A conserved protein with AN1 zinc finger and ubiquitin-like domains modulates Cdc48 (p97) function in the ubiquitin-proteasome pathway. 2412 1

SNF2 family ATPases are ATP-dependent motors that often function in multisubunit complexes to regulate chromatin structure. Although the central role of SNF2 ATPases in chromatin biology is well established, mechanisms by which their catalytic activities are regulated by additional subunits of chromatin-remodeling complexes are less well understood. Here we present evidence that the human Inositol auxotrophy 80 (Ino80) SNF2 ATPase is subject to regulation at multiple levels in the INO80 chromatin-remodeling complex. The zinc finger histidine triad domain-containing protein Ies2 (Ino Eighty Subunit 2) functions as a potent activator of the intrinsic catalytic activity of the Ino80 ATPase, whereas the YL-1 family Ies6 (Ino Eighty Subunit 6) and actin-related Arp5 proteins function together to promote binding of the Ino80 ATPase to nucleosomes. These findings support the idea that both substrate recognition and the intrinsic catalytic activities of SNF2 ATPases have evolved as important sites for their regulation.
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PMID:Multiple modes of regulation of the human Ino80 SNF2 ATPase by subunits of the INO80 chromatin-remodeling complex. 2429 34

Pleomorphic adenoma gene like-2 (PLAGL2), a member of the PLAG gene family, is a C2H2 zinc finger transcriptional factor that is involved in cellular transformation and apoptosis. In this report, we show that PLAGL2 is associated with the organization of stress fibers and with small guanosine triphosphatase (GTPase) activity. Depletion of PLAGL2 in two different ovarian cancer cell lines, ES-2 and HEY, induced activation of RhoA, whereas activity of Rac1 was suppressed. Organization of actin stress fibers and focal adhesions was significantly promoted by PLAGL2 knockdown in a RhoA-dependent manner. Conversely, exogenous expression of PLAGL2 in MDA-MB-231 cells, a breast cancer cell line, resulted in the activation of Rac1 and the inactivation of RhoA. In addition, PLAGL2 expression induced lamellipodia formation and disruption of stress fiber formation. Finally, we show that CHN1 expression is essential for Rac1 inactivation in PLAGL2-depleted cells. Our results demonstrate a crucial role of PLAGL2 in actin dynamics and give further insight into the role of PLAGL2 in cellular transformation and apoptosis.
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PMID:PLAGL2 regulates actin cytoskeletal architecture and cell migration. 2467 30


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