scholarly journals Regulation of Transcription at theSaccharomyces cerevisiae Start Transition by Stb1, a Swi6-Binding Protein

1999 ◽  
Vol 19 (8) ◽  
pp. 5267-5278 ◽  
Author(s):  
Yuen Ho ◽  
Michael Costanzo ◽  
Lynda Moore ◽  
Ryuji Kobayashi ◽  
Brenda J. Andrews
Keyword(s):  
Cell Wall Biosynthesis ◽  
Regulation Of Transcription ◽  
Cyclin Dependent Kinase ◽  
Cyclin Dependent Kinases ◽  
The Common ◽  
Start Transition ◽  
Cyclin Genes ◽  
Two Hybrid

ABSTRACT In Saccharomyces cerevisiae, gene expression in the late G1 phase is activated by two transcription factors, SBF and MBF. SBF contains the Swi4 and Swi6 proteins and activates the transcription of G1 cyclin genes, cell wall biosynthesis genes, and the HO gene. MBF is composed of Mbp1 and Swi6 and activates the transcription of genes required for DNA synthesis. Mbp1 and Swi4 are the DNA binding subunits for MBF and SBF, while the common subunit, Swi6, is presumed to play a regulatory role in both complexes. We show that Stb1, a protein first identified in a two-hybrid screen with the transcriptional repressor Sin3, binds Swi6 in vitro. The STB1 transcript was cell cycle periodic and peaked in late G1 phase. In vivo accumulation of Stb1 phosphoforms was dependent on CLN1, CLN2, andCLN3, which encode G1-specific cyclins for the cyclin-dependent kinase Cdc28, and Stb1 was phosphorylated by Cln-Cdc28 kinases in vitro. Deletion of STB1 caused an exacerbated delay in G1 progression and the onset of Start transcription in a cln3Δ strain. Our results suggest a role for STB1 in controlling the timing of Start transcription that is revealed in the absence of the G1regulator CLN3, and they implicate Stb1 as an in vivo target of G1-specific cyclin-dependent kinases.

scholarly journals Phosphorylation of the myristoylated protein kinase C substrate MARCKS by the cyclin E–cyclin-dependent kinase 2 complex in vitro

1999 ◽  
Vol 340 (3) ◽  
pp. 775-782 ◽  
Author(s):  
Stéphane MANENTI ◽  
Emiko YAMAUCHI ◽  
Odile SOROKINE ◽  
Martine KNIBIEHLER ◽  
Alain VAN DORSSELAER ◽  
...  
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Cyclin E ◽  
Cyclin Dependent Kinase ◽  
Kinase Substrate ◽  
Cyclin Dependent Kinases ◽  
Kinase C ◽  
Cdk2 Complex

The myristoylated alanine-rich C-kinase substrate (MARCKS) purified from brain was recently characterized as a proline-directed kinase(s) substrate in vivo [Taniguchi, Manenti, Suzuki and Titani (1994) J. Biol. Chem. 269, 18299-18302]. Here we have investigated the phosphorylation of MARCKS by various cyclin-dependent kinases (Cdks) in vitro. We established that Cdk2, Cdk4 and, to a smaller extent, Cdk1 that have been immunoprecipitated from cellular extracts phosphorylate MARCKS. Comparison of MARCKS phosphorylation by protein kinase C (PKC) and by the purified cyclin E-Cdk2 complex suggested that two residues were phosphorylated by Cdk2 under these conditions. To identify these sites, Cdk2-phosphorylated MARCKS was digested with lysyl endoprotease and analysed by electrospray MS. Comparison with the digests obtained from the unphosphorylated protein demonstrated that two peptides, Gly12-Lys30 and Ala138-Lys152, were phosphorylated by cyclin E-Cdk2. The identity of these peptides was confirmed by automatic Edman degradation. On the basis of the consensus phosphorylation sequence described for Cdk2, and on MS/MS analysis of the Ala138-Lys152 peptide, we concluded that Ser27, one of the phosphorylation sites identified in vivo, and Thr150 were the Cdk2 targets in vitro. None of the other sites described in vivo were phosphorylated in these conditions. Interestingly, a preliminary phosphorylation of MARCKS by PKC improved the initial rate of phosphorylation by Cdk2 without modifying the number of sites concerned. In contrast, phosphorylation of MARCKS by Cdk2 did not significantly affect further phosphorylation by PKC.

scholarly journals Inhibition of Cyclin-Dependent Kinases Improves CA1 Neuronal Survival and Behavioral Performance after Global Ischemia in the Rat

2002 ◽  
Vol 22 (2) ◽  
pp. 171-182 ◽  
Author(s):  
Fuhu Wang ◽  
Dale Corbett ◽  
Hitoshi Osuga ◽  
Sachiko Osuga ◽  
Joh-E Ikeda ◽  
...  
Keyword(s):  
Kinase Inhibitor ◽  
Core Body Temperature ◽  
Protein A ◽  
Extended Period ◽  
Global Ischemia ◽  
Cyclin Dependent Kinase ◽  
Kinase Inhibition ◽  
Cyclin Dependent Kinases

Increasing evidence suggests that cyclin-dependent kinases participate in neuronal death induced by multiple stresses in vitro. However, their role in cell death paradigms in vivo is not well characterized. Accordingly, the authors examined whether cyclin-dependent kinase inhibition resulted in functionally relevant and sustained neuroprotection in a model of global ischemia. Intracerebroventricular administration of the cyclin-dependent kinase inhibitor flavopiridol, immediately or at 4 hours postreperfusion after a global insult, reduced injury in the CA1 of the hippocampus when examined 7 days after reperfusion. No significant protection was observed when flavopiridol was administered 8 hours after reperfusion. The tumor-suppressor retinoblastoma protein, a substrate of cyclin-dependent kinase, was phosphorylated on a cyclin-dependent kinase consensus site after the global insult; this phosphorylation was inhibited by flavopiridol administration. Importantly, flavopiridol had no effect on core body temperature, suggesting that the mechanism of neuroprotection was through cyclin-dependent kinase inhibition but not through hypothermia. Furthermore, inhibition of cyclin-dependent kinases improved spatial learning behavior as assessed by the Morris water maze 7 to 9 days after reperfusion. However, the histologic protection observed at day 7 was absent 28 days after reperfusion. These results indicate that cyclin-dependent kinase inhibition provides an extended period of morphologic and functional neuroprotection that may allow time for other neuroprotective modalities to be introduced.

scholarly journals Cyclin-dependent Kinases Participate in Death of Neurons Evoked by DNA-damaging Agents

1998 ◽  
Vol 143 (2) ◽  
pp. 457-467 ◽  
Author(s):  
David S. Park ◽  
Erick J. Morris ◽  
Jaya Padmanabhan ◽  
Michael L. Shelanski ◽  
Herbert M. Geller ◽  
...  
Keyword(s):  
Cortical Neurons ◽  
Sindbis Virus ◽  
Kinase Inhibitors ◽  
Sympathetic Neurons ◽  
Dominant Negative ◽  
Cyclin Dependent Kinase ◽  
Cyclin Dependent Kinases ◽  
Dna Damaging Agents

Previous reports have indicated that DNA-damaging treatments including certain anticancer therapeutics cause death of postmitotic nerve cells both in vitro and in vivo. Accordingly, it has become important to understand the signaling events that control this process. We recently hypothesized that certain cell cycle molecules may play an important role in neuronal death signaling evoked by DNA damage. Consequently, we examined whether cyclin-dependent kinase inhibitors (CKIs) and dominant-negative (DN) cyclin-dependent kinases (CDK) protect sympathetic and cortical neurons against DNA-damaging conditions. We show that Sindbis virus–induced expression of CKIs p16ink4, p21waf/cip1, and p27kip1, as well as DN-Cdk4 and 6, but not DN-Cdk2 or 3, protect sympathetic neurons against UV irradiation– and AraC-induced death. We also demonstrate that the CKIs p16 and p27 as well as DN-Cdk4 and 6 but not DN-Cdk2 or 3 protect cortical neurons from the DNA damaging agent camptothecin. Finally, in consonance with our hypothesis and these results, cyclin D1–associated kinase activity is rapidly and highly elevated in cortical neurons upon camptothecin treatment. These results suggest that postmitotic neurons may utilize Cdk4 and 6, signals that normally control proliferation, to mediate death signaling resulting from DNA-damaging conditions.

scholarly journals BUR1 and BUR2 Encode a Divergent Cyclin-Dependent Kinase–Cyclin Complex Important for Transcription In Vivo

2000 ◽  
Vol 20 (19) ◽  
pp. 7080-7087 ◽  
Author(s):  
Sheng Yao ◽  
Aaron Neiman ◽  
Gregory Prelich
Keyword(s):  
Protein Kinase ◽  
Genetic Selection ◽  
Cyclin Dependent Kinase ◽  
Selection For ◽  
Mutant Phenotypes ◽  
Two Hybrid ◽  
Putative Protein Kinase

ABSTRACT BUR1 and BUR2 were previously identified by a genetic selection for mutations that increase transcription from basal promoters in vivo. BUR1 encoded a putative protein kinase with greatest similarity to members of the cyclin-dependent kinase (CDK) family, although that similarity was not sufficient to classify it as a CDK. It was also not known whether Bur1 activity was cyclin dependent and, if so, which cyclins stimulated Bur1. The molecular cloning and characterization of BUR2 presented here sheds light on these issues. Genetic analysis indicates thatBUR2 function is intimately related to that ofBUR1: bur1 and bur2 mutations cause nearly identical spectra of mutant phenotypes, and overexpression ofBUR1 suppresses a bur2 null allele. Biochemical analysis has provided a molecular basis for these genetic observations. We find that BUR2 encodes a cyclin for the Bur1 protein kinase, based on the following evidence. First, the BUR2amino acid sequence reveals similarity to the cyclins; second, Bur1 and Bur2 coimmunoprecipitate from crude extracts and interact in the two-hybrid system; and third, BUR2 is required for Bur1 kinase activity in vitro. Our combined genetic and biochemical results therefore indicate that Bur1 and Bur2 comprise a divergent CDK-cyclin complex that has an important functional role during transcription in vivo.

scholarly journals Suppression of HIV-1 Expression by Inhibitors of Cyclin-Dependent Kinases Promotes Differentiation of Infected Podocytes

2001 ◽  
Vol 12 (12) ◽  
pp. 2827-2831
Author(s):  
Peter J. Nelson ◽  
Irwin H. Gelman ◽  
Paul E. Klotman
Keyword(s):  
Therapeutic Strategy ◽  
Response Analysis ◽  
Cyclin Dependent Kinase ◽  
Differentiation Markers ◽  
Inhibition Of Proliferation ◽  
Cyclin Dependent Kinases ◽  
Glomerular Lesions ◽  
Hiv 1

ABSTRACT. The glomerular lesions of HIV-associated nephropathy (HIVAN) are associated with the expression of HIV-1 in podocytes. Infected podocytes proliferate and lose several differentiation markersin vivoandin vitro,which suggests that HIV-1 gene expression induces these changes. Flavopiridol and roscovitine, newly identified inhibitors of cyclin-dependent kinase-9, markedly decrease HIV-1 promoter activity in cell lines of various lineages. In this study, the inhibitors were used to determine whether suppression of HIV-1 transcription in infected podocytes correlated with an inhibition of proliferation and a return to the differentiated phenotype. Dose-response analysis showed that both flavopiridol and roscovitine reversibly suppressed HIV-1 transcription in podocytesin vitroat an IC50of 25 nM and 3 μM, respectively. Despite equivalent suppression of HIV-1 transcription, roscovitine was a more effective inhibitor of podocyte proliferation than flavopiridol. Suppression of HIV-1 transcription by flavopiridol or roscovitine was marked by re-expression of the podocyte differentiation markers, synaptopodin and podocalyxin. These results suggest that inhibition of HIV-1 transcription decreases podocyte proliferation and permits the reexpression of differentiation markers. Thus, suppression of HIV-1 transcription by selective cyclin-dependent kinase-9 inhibitors may be a useful therapeutic strategy for the treatment of HIVAN.

The Application of the Cold Atmospheric Plasma-Activated Solutions in Cancer Treatment

2018 ◽  
Vol 18 (6) ◽  
pp. 769-775 ◽  
Author(s):  
Dayun Yan ◽  
Jonathan H. Sherman ◽  
Michael Keidar
Keyword(s):  
Cancer Treatment ◽  
Atmospheric Plasma ◽  
Current Status ◽  
Cold Atmospheric Plasma ◽  
Anti Cancer ◽  
Long Time ◽  
Key Topics ◽  
The Common

Background: Over the past five years, the cold atmospheric plasma-activated solutions (PAS) have shown their promissing application in cancer treatment. Similar as the common direct cold plasma treatment, PAS shows a selective anti-cancer capacity in vitro and in vivo. However, different from the direct cold atmospheric plasma (CAP) treatment, PAS can be stored for a long time and can be used without dependence on a CAP device. The research on PAS is gradually becoming a hot topic in plasma medicine. Objectives: In this review, we gave a concise but comprehensive summary on key topics about PAS including the development, current status, as well as the main conclusions about the anti-cancer mechanism achieved in past years. The approaches to make strong and stable PAS are also summarized.

scholarly journals Stu2p binds tubulin and undergoes an open-to-closed conformational change

2006 ◽  
Vol 172 (7) ◽  
pp. 1009-1022 ◽  
Author(s):  
Jawdat Al-Bassam ◽  
Mark van Breugel ◽  
Stephen C. Harrison ◽  
Anthony Hyman
Keyword(s):  
Conformational Change ◽  
Conformational Transition ◽  
Budding Yeast ◽  
Microtubule Dynamics ◽  
Open Structure ◽  
Microtubule Associated Proteins ◽  
Associated Proteins ◽  
The Common

Stu2p from budding yeast belongs to the conserved Dis1/XMAP215 family of microtubule-associated proteins (MAPs). The common feature of proteins in this family is the presence of HEAT repeat–containing TOG domains near the NH2 terminus. We have investigated the functions of the two TOG domains of Stu2p in vivo and in vitro. Our data suggest that Stu2p regulates microtubule dynamics through two separate activities. First, Stu2p binds to a single free tubulin heterodimer through its first TOG domain. A large conformational transition in homodimeric Stu2p from an open structure to a closed one accompanies the capture of a single free tubulin heterodimer. Second, Stu2p has the capacity to associate directly with microtubule ends, at least in part, through its second TOG domain. These two properties lead to the stabilization of microtubules in vivo, perhaps by the loading of tubulin dimers at microtubule ends. We suggest that this mechanism of microtubule regulation is a conserved feature of the Dis1/XMAP215 family of MAPs.

scholarly journals Evidence for the Involvement of the Glc7-Reg1 Phosphatase and the Snf1-Snf4 Kinase in the Regulation of INO1 Transcription in Saccharomyces cerevisiae

Genetics ◽  
1999 ◽  
Vol 152 (1) ◽  
pp. 73-87 ◽  
Author(s):  
Margaret K Shirra ◽  
Karen M Arndt
Keyword(s):  
Rna Polymerase Ii ◽  
Glucose Repression ◽  
Snf1 Kinase ◽  
Glucose Levels ◽  
Recessive Mutations ◽  
Mutant Strains ◽  
Rna Polymerase Ii Transcription ◽  
Two Hybrid

AbstractBinding of the TATA-binding protein (TBP) to the promoter is a pivotal step in RNA polymerase II transcription. To identify factors that regulate TBP, we selected for suppressors of a TBP mutant that exhibits promoter-specific defects in activated transcription in vivo and severely reduced affinity for TATA boxes in vitro. Dominant mutations in SNF4 and recessive mutations in REG1, OPI1, and RTF2 were isolated that specifically suppress the inositol auxotrophy of the TBP mutant strains. OPI1 encodes a repressor of INO1 transcription. REG1 and SNF4 encode regulators of the Glc7 phosphatase and Snf1 kinase, respectively, and have well-studied roles in glucose repression. In two-hybrid assays, one SNF4 mutation enhances the interaction between Snf4 and Snf1. Suppression of the TBP mutant by our reg1 and SNF4 mutations appears unrelated to glucose repression, since these mutations do not alleviate repression of SUC2, and glucose levels have little effect on INO1 transcription. Moreover, mutations in TUP1, SSN6, and GLC7, but not HXK2 and MIG1, can cause suppression. Our data suggest that association of TBP with the TATA box may be regulated, directly or indirectly, by a substrate of Snf1. Analysis of INO1 transcription in various mutant strains suggests that this substrate is distinct from Opi1.

scholarly journals A Wolf in Another Wolf’s Clothing: Post-Genomic Regulation Dictates Venom Profiles of Medically-Important Cryptic Kraits in India

Toxins ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 69 ◽  
Author(s):  
Kartik Sunagar ◽  
Suyog Khochare ◽  
R. R. Senji Laxme ◽  
Saurabh Attarde ◽  
Paulomi Dam ◽  
...  
Keyword(s):  
Negative Impact ◽  
Indian Subcontinent ◽  
Clinical Effectiveness ◽  
Venom Gland ◽  
Western India ◽  
The Common ◽  
Genomic Regulation

The Common Krait (Bungarus caeruleus) shares a distribution range with many other ‘phenotypically-similar’ kraits across the Indian subcontinent. Despite several reports of fatal envenomings by other Bungarus species, commercial Indian antivenoms are only manufactured against B. caeruleus. It is, therefore, imperative to understand the distribution of genetically distinct lineages of kraits, the compositional differences in their venoms, and the consequent impact of venom variation on the (pre)clinical effectiveness of antivenom therapy. To address this knowledge gap, we conducted phylogenetic and comparative venomics investigations of kraits in Southern and Western India. Phylogenetic reconstructions using mitochondrial markers revealed a new species of krait, Romulus’ krait (Bungarus romulusi sp. nov.), in Southern India. Additionally, we found that kraits with 17 mid-body dorsal scale rows in Western India do not represent a subspecies of the Sind Krait (B. sindanus walli) as previously believed, but are genetically very similar to B. sindanus in Pakistan. Furthermore, venom proteomics and comparative transcriptomics revealed completely contrasting venom profiles. While the venom gland transcriptomes of all three species were highly similar, venom proteomes and toxicity profiles differed significantly, suggesting the prominent role of post-genomic regulatory mechanisms in shaping the venoms of these cryptic kraits. In vitro venom recognition and in vivo neutralisation experiments revealed a strong negative impact of venom variability on the preclinical performance of commercial antivenoms. While the venom of B. caeruleus was neutralised as per the manufacturer’s claim, performance against the venoms of B. sindanus and B. romulusi was poor, highlighting the need for regionally-effective antivenoms in India.

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