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Full-Text Articles in Other Medical Specialties

Multisite Phosphorylation Of The Sum1 Transcriptional Repressor By S-Phase Kinases Controls Exit From Meiotic Prophase In Yeast., Daniel Corbi, Sham Sunder, Michael Weinreich, Aikaterini Skokotas, Erica S Johnson, Edward Winter Jun 2014

Multisite Phosphorylation Of The Sum1 Transcriptional Repressor By S-Phase Kinases Controls Exit From Meiotic Prophase In Yeast., Daniel Corbi, Sham Sunder, Michael Weinreich, Aikaterini Skokotas, Erica S Johnson, Edward Winter

Department of Biochemistry and Molecular Biology Faculty Papers

Activation of the meiotic transcription factor Ndt80 is a key regulatory transition in the life cycle of Saccharomyces cerevisiae because it triggers exit from pachytene and entry into meiosis. The NDT80 promoter is held inactive by a complex containing the DNA-binding protein Sum1 and the histone deacetylase Hst1. Meiosis-specific phosphorylation of Sum1 by the protein kinases Cdk1, Ime2, and Cdc7 is required for NDT80 expression. Here, we show that the S-phase-promoting cyclin Clb5 activates Cdk1 to phosphorylate most, and perhaps all, of the 11 minimal cyclin-dependent kinase (CDK) phospho-consensus sites (S/T-P) in Sum1. Nine of these sites can individually promote …


The P53-Induced Factor Ei24 Inhibits Nuclear Import Through An Importin Β-Binding-Like Domain., Kim G Lieu, Eun-Hee Shim, Jinling Wang, Ravi K Lokareddy, Tao Tao, Gino Cingolani, Gerard P Zambetti, David A Jans May 2014

The P53-Induced Factor Ei24 Inhibits Nuclear Import Through An Importin Β-Binding-Like Domain., Kim G Lieu, Eun-Hee Shim, Jinling Wang, Ravi K Lokareddy, Tao Tao, Gino Cingolani, Gerard P Zambetti, David A Jans

Department of Biochemistry and Molecular Biology Faculty Papers

The etoposide-induced protein Ei24 was initially identified as a p53-responsive, proapoptotic factor, but no clear function has been described. Here, we use a nonbiased proteomics approach to identify members of the importin (IMP) family of nuclear transporters as interactors of Ei24 and characterize an IMPβ-binding-like (IBBL) domain within Ei24. We show that Ei24 can bind specifically to IMPβ1 and IMPα2, but not other IMPs, and use a mutated IMPβ1 derivative to show that Ei24 binds to the same site on IMPβ1 as the IMPα IBB. Ectopic expression of Ei24 reduced the extent of IMPβ1- or IMPα/β1-dependent nuclear protein import specifically, …


Disruption Of Drosophila Melanogaster Lipid Metabolism Genes Causes Tissue Overgrowth Associated With Altered Developmental Signaling., Takeshi Sasamura, Kenji Matsuno, Mark E Fortini Nov 2013

Disruption Of Drosophila Melanogaster Lipid Metabolism Genes Causes Tissue Overgrowth Associated With Altered Developmental Signaling., Takeshi Sasamura, Kenji Matsuno, Mark E Fortini

Department of Biochemistry and Molecular Biology Faculty Papers

Developmental patterning requires the precise interplay of numerous intercellular signaling pathways to ensure that cells are properly specified during tissue formation and organogenesis. The spatiotemporal function of many developmental pathways is strongly influenced by the biosynthesis and intracellular trafficking of signaling components. Receptors and ligands must be trafficked to the cell surface where they interact, and their subsequent endocytic internalization and endosomal trafficking is critical for both signal propagation and its down-modulation. In a forward genetic screen for mutations that alter intracellular Notch receptor trafficking in Drosophila melanogaster, we recovered mutants that disrupt genes encoding serine palmitoyltransferase and acetyl-CoA carboxylase. …


The Drosophila Eve Insulator Homie Promotes Eve Expression And Protects The Adjacent Gene From Repression By Polycomb Spreading., Miki Fujioka, Guizhi Sun, James B Jaynes Oct 2013

The Drosophila Eve Insulator Homie Promotes Eve Expression And Protects The Adjacent Gene From Repression By Polycomb Spreading., Miki Fujioka, Guizhi Sun, James B Jaynes

Department of Biochemistry and Molecular Biology Faculty Papers

Insulators can block the action of enhancers on promoters and the spreading of repressive chromatin, as well as facilitating specific enhancer-promoter interactions. However, recent studies have called into question whether the activities ascribed to insulators in model transgene assays actually reflect their functions in the genome. The Drosophila even skipped (eve) gene is a Polycomb (Pc) domain with a Pc-group response element (PRE) at one end, flanked by an insulator, an arrangement also seen in other genes. Here, we show that this insulator has three major functions. It blocks the spreading of the eve Pc domain, preventing repression of the …


G Protein-Coupled Receptor Kinase 2 (Grk2) Is Localized To Centrosomes And Mediates Epidermal Growth Factor-Promoted Centrosomal Separation., Christopher H So, Allison Michal, Konstantin E Komolov, Jiansong Luo, Jeffrey L Benovic Sep 2013

G Protein-Coupled Receptor Kinase 2 (Grk2) Is Localized To Centrosomes And Mediates Epidermal Growth Factor-Promoted Centrosomal Separation., Christopher H So, Allison Michal, Konstantin E Komolov, Jiansong Luo, Jeffrey L Benovic

Department of Biochemistry and Molecular Biology Faculty Papers

G protein-coupled receptor kinases (GRKs) play a central role in regulating receptor signaling, but recent studies suggest a broader role in modulating normal cellular functions. For example, GRK5 has been shown to localize to centrosomes and regulate microtubule nucleation and cell cycle progression. Here we demonstrate that GRK2 is also localized to centrosomes, although it has no role in centrosome duplication or microtubule nucleation. Of interest, knockdown of GRK2 inhibits epidermal growth factor receptor (EGFR)-mediated separation of duplicated centrosomes. This EGFR/GRK2-mediated process depends on the protein kinases mammalian STE20-like kinase 2 (Mst2) and Nek2A but does not involve polo-like kinase …


Leukemia-Associated Rhogef (Larg) Is A Novel Rhogef In Cytokinesis And Required For The Proper Completion Of Abscission., Matthew K Martz, Elda Grabocka, Neil Beeharry, Timothy J Yen, Philip B Wedegaertner Sep 2013

Leukemia-Associated Rhogef (Larg) Is A Novel Rhogef In Cytokinesis And Required For The Proper Completion Of Abscission., Matthew K Martz, Elda Grabocka, Neil Beeharry, Timothy J Yen, Philip B Wedegaertner

Department of Biochemistry and Molecular Biology Faculty Papers

Proper completion of mitosis requires the concerted effort of multiple RhoGEFs. Here we show that leukemia-associated RhoGEF (LARG), a RhoA-specific RGS-RhoGEF, is required for abscission, the final stage of cytokinesis, in which the intercellular membrane is cleaved between daughter cells. LARG colocalizes with α-tubulin at the spindle poles before localizing to the central spindle. During cytokinesis, LARG is condensed in the midbody, where it colocalizes with RhoA. HeLa cells depleted of LARG display apoptosis during cytokinesis with unresolved intercellular bridges, and rescue experiments show that expression of small interfering RNA-resistant LARG prevents this apoptosis. Moreover, live cell imaging of LARG-depleted …


Global Analysis Of Sumo Chain Function Reveals Multiple Roles In Chromatin Regulation., Tharan Srikumar, Megan C Lewicki, Michael Costanzo, Johnny M Tkach, Harm Van Bakel, Kyle Tsui, Erica S Johnson, Grant W Brown, Brenda J Andrews, Charles Boone, Guri Giaever, Corey Nislow, Brian Raught Apr 2013

Global Analysis Of Sumo Chain Function Reveals Multiple Roles In Chromatin Regulation., Tharan Srikumar, Megan C Lewicki, Michael Costanzo, Johnny M Tkach, Harm Van Bakel, Kyle Tsui, Erica S Johnson, Grant W Brown, Brenda J Andrews, Charles Boone, Guri Giaever, Corey Nislow, Brian Raught

Department of Biochemistry and Molecular Biology Faculty Papers

Like ubiquitin, the small ubiquitin-related modifier (SUMO) proteins can form oligomeric "chains," but the biological functions of these superstructures are not well understood. Here, we created mutant yeast strains unable to synthesize SUMO chains (smt3(allR)) and subjected them to high-content microscopic screening, synthetic genetic array (SGA) analysis, and high-density transcript profiling to perform the first global analysis of SUMO chain function. This comprehensive assessment identified 144 proteins with altered localization or intensity in smt3(allR) cells, 149 synthetic genetic interactions, and 225 mRNA transcripts (primarily consisting of stress- and nutrient-response genes) that displayed a >1.5-fold increase in expression levels. This information-rich …


Mitochondrial Lysyl-Trna Synthetase Independent Import Of Trna Lysine Into Yeast Mitochondria., Naresh Babu V Sepuri, Madhavi Gorla, Michael P King Apr 2012

Mitochondrial Lysyl-Trna Synthetase Independent Import Of Trna Lysine Into Yeast Mitochondria., Naresh Babu V Sepuri, Madhavi Gorla, Michael P King

Department of Biochemistry and Molecular Biology Faculty Papers

Aminoacyl tRNA synthetases play a central role in protein synthesis by charging tRNAs with amino acids. Yeast mitochondrial lysyl tRNA synthetase (Msk1), in addition to the aminoacylation of mitochondrial tRNA, also functions as a chaperone to facilitate the import of cytosolic lysyl tRNA. In this report, we show that human mitochondrial Kars (lysyl tRNA synthetase) can complement the growth defect associated with the loss of yeast Msk1 and can additionally facilitate the in vitro import of tRNA into mitochondria. Surprisingly, the import of lysyl tRNA can occur independent of Msk1 in vivo. This suggests that an alternative mechanism is present …


Genes Adopt Non-Optimal Codon Usage To Generate Cell Cycle-Dependent Oscillations In Protein Levels., Milana Frenkel-Morgenstern, Tamar Danon, Thomas Christian, Takao Igarashi, Lydia Cohen, Ya-Ming Hou, Lars Juhl Jensen Jan 2012

Genes Adopt Non-Optimal Codon Usage To Generate Cell Cycle-Dependent Oscillations In Protein Levels., Milana Frenkel-Morgenstern, Tamar Danon, Thomas Christian, Takao Igarashi, Lydia Cohen, Ya-Ming Hou, Lars Juhl Jensen

Department of Biochemistry and Molecular Biology Faculty Papers

The cell cycle is a temporal program that regulates DNA synthesis and cell division. When we compared the codon usage of cell cycle-regulated genes with that of other genes, we discovered that there is a significant preference for non-optimal codons. Moreover, genes encoding proteins that cycle at the protein level exhibit non-optimal codon preferences. Remarkably, cell cycle-regulated genes expressed in different phases display different codon preferences. Here, we show empirically that transfer RNA (tRNA) expression is indeed highest in the G2 phase of the cell cycle, consistent with the non-optimal codon usage of genes expressed at this time, and lowest …


Potential For Interdependent Development Of Trna Determinants For Aminoacylation And Ribosome Decoding., Cuiping Liu, Howard Gamper, Hanqing Liu, Barry S Cooperman, Ya-Ming Hou Jan 2011

Potential For Interdependent Development Of Trna Determinants For Aminoacylation And Ribosome Decoding., Cuiping Liu, Howard Gamper, Hanqing Liu, Barry S Cooperman, Ya-Ming Hou

Department of Biochemistry and Molecular Biology Faculty Papers

Although the nucleotides in tRNA required for aminoacylation are conserved in evolution, bacterial aminoacyl-transfer RNA synthetases are unable to acylate eukaryotic tRNA. The cross-species barrier may be due to the absence of eukaryote-specific domains from bacterial aminoacyl-transfer RNA synthetases. Here we show that whereas Escherichia coli CysRS cannot acylate human tRNA(Cys), the fusion of a eukaryote-specific domain of human CysRS overcomes the cross-species barrier in human tRNA(Cys). In addition to enabling recognition of the sequence differences in the tertiary core of tRNA(Cys), the fused eukaryotic domain redirects the specificity of E. coli CysRS from the A37 present in bacterial tRNA(Cys) …


Enzymatic Synthesis Of Structure-Free Dna With Pseudo-Complementary Properties., Georges Lahoud, Victor Timoshchuk, Alexandre Lebedev, Miguel De Vega, Margarita Salas, Khalil Arar, Ya-Ming Hou, Howard Gamper Jun 2008

Enzymatic Synthesis Of Structure-Free Dna With Pseudo-Complementary Properties., Georges Lahoud, Victor Timoshchuk, Alexandre Lebedev, Miguel De Vega, Margarita Salas, Khalil Arar, Ya-Ming Hou, Howard Gamper

Department of Biochemistry and Molecular Biology Faculty Papers

Long single-stranded DNAs and RNAs possess considerable secondary structure under conditions that support stable hybrid formation with oligonucleotides. Consequently, different oligomeric probes can hybridize to the same target with efficiencies that vary by several orders of magnitude. The ability to enzymatically generate structure-free single-stranded copies of any nucleic acid without impairing Watson-Crick base pairing to short probes would eliminate this problem and significantly improve the performance of many oligonucleotide-based applications. Synthetic nucleic acids that exhibit these properties are defined as pseudo-complementary. Previously, we described a pseudo-complementary A-T couple consisting of 2-aminoadenine (nA) and 2-thiothymine (sT) bases. The nA-sT couple is …