12 results match your criteria i-associated nascent

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Heterogeneous nuclear ribonucleoprotein A1 in health and neurodegenerative disease: from structural insights to post-transcriptional regulatory roles.

Mol Cell Neurosci 2013 Sep 14;56:436-46. Epub 2012 Dec 14.

Dept of Biological Chemistry, The Life Sciences Institute and The Edmond and Lily Safra Center of Brain Science, The Hebrew University of Jerusalem, 91904, Israel.

Heterogeneous nuclear ribonucleoproteins (hnRNPs) are a family of conserved nuclear proteins that associate with nascent RNA polymerase II transcripts to yield hnRNP particles, playing key roles in mRNA metabolism, DNA-related functions and microRNA biogenesis. HnRNPs accompany transcripts from stages of transcriptional regulation through splicing and post-transcriptional regulation, and are believed to affect the majority of expressed genes in mammals. Most hnRNP mRNA transcripts undergo alternative splicing and post-translational modifications, to yield a remarkable diversity of proteins with numerous functional elements that work in concert in their multiple functions. Read More

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September 2013

Rrp5p, Noc1p and Noc2p form a protein module which is part of early large ribosomal subunit precursors in S. cerevisiae.

Nucleic Acids Res 2013 Jan 2;41(2):1191-210. Epub 2012 Dec 2.

Universität Regensburg, Biochemie-Zentrum Regensburg (BZR), Lehrstuhl Biochemie III, 93053 Regensburg, Germany.

Eukaryotic ribosome biogenesis requires more than 150 auxiliary proteins, which transiently interact with pre-ribosomal particles. Previous studies suggest that several of these biogenesis factors function together as modules. Using a heterologous expression system, we show that the large ribosomal subunit (LSU) biogenesis factor Noc1p of Saccharomyces cerevisiae can simultaneously interact with the LSU biogenesis factor Noc2p and Rrp5p, a factor required for biogenesis of the large and the small ribosomal subunit. Read More

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January 2013

MHC I-associated peptides preferentially derive from transcripts bearing miRNA response elements.

Blood 2012 Jun 21;119(26):e181-91. Epub 2012 Mar 21.

Institute for Research in Immunology and Cancer, Université deMontréal, Montréal, QC, Canada.

MHC I-associated peptides (MIPs) play an essential role in normal homeostasis and diverse pathologic conditions. MIPs derive mainly from defective ribosomal products (DRiPs), a subset of nascent proteins that fail to achieve a proper conformation and the physical nature of which remains elusive. In the present study, we used high-throughput proteomic and transcriptomic methods to unravel the structure and biogenesis of MIPs presented by HLA-A and HLA-B molecules on human EBV-infected B lymphocytes from 4 patients. Read More

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Redox-regulated peptide transfer from the transporter associated with antigen processing to major histocompatibility complex class I molecules by protein disulfide isomerase.

Antioxid Redox Signal 2011 Aug 11;15(3):621-33. Epub 2011 May 11.

Department of Biological Sciences, National Creative Research Center for Antigen Presentation, Seoul National University, Seoul, South Korea.

Most antigenic peptides are generated by proteasomes in the cytosol and are transported by the transporter associated with antigen processing (TAP) into the endoplasmic reticulum, where they bind with nascent major histocompatibilitiy complex class I molecule (MHC-I). Although the overall process of peptide-MHC-I complex assembly is well studied, the mechanism by which free peptides are delivered from TAP to MHC-I is unknown. In this study, we investigated the possible role of protein disulfide isomerase (PDI) as a peptide carrier between TAP and MHC-I. Read More

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E-cadherin dis-engagement activates the Rap1 GTPase.

J Cell Biochem 2008 Nov;105(4):1027-37

Department of Biochemistry and Molecular Biology, Indiana University School of Medicine and Walther Oncology Center, Indianapolis, Indiana 46202, USA.

E-cadherin based adherens junctions are finely regulated by multiple cellular signaling events. Here we show that the Ras-related Rap1 GTPase is enriched in regions of nascent cell-cell contacts and strengthens E-cadherin junctions: constitutively active Rap1 expressing MDCK cells exhibit increased junctional contact and resisted calcium depletion-induced cell-cell junction disruption. E-cadherin disengagement activated Rap1 and this correlated with E-cadherin association with the Rap GEFs, C3G and PDZ-GEF I. Read More

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November 2008

Budding yeast RNA polymerases I and II employ parallel mechanisms of transcriptional termination.

Genes Dev 2008 Apr;22(8):1082-92

Sir William Dunn School of Pathology, Oxford OX1 3RE, United Kingdom.

Both RNA polymerase I and II (Pol I and Pol II) in budding yeast employ a functionally homologous "torpedo-like" mechanism to promote transcriptional termination. For two well-defined Pol II-transcribed genes, CYC1 and PMA1, we demonstrate that both Rat1p exonuclease and Sen1p helicase are required for efficient termination by promoting degradation of the nascent transcript associated with Pol II, following mRNA 3' end processing. Similarly, Pol I termination relies on prior Rnt1p cleavage at the 3' end of the pre-rRNA 35S transcript. Read More

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Quantitative analysis of ABCA1-dependent compartmentalization and trafficking of apolipoprotein A-I: implications for determining cellular kinetics of nascent high density lipoprotein biogenesis.

J Biol Chem 2008 Apr 24;283(17):11164-75. Epub 2008 Jan 24.

Cardiovascular Genetics Laboratory, Division of Cardiology, McGill University Health Centre/Royal Victoria Hospital, Montréal, Québec H3A 1A1, Canada.

The molecular mechanisms underlying the apoA-I/ABCA1 endocytic trafficking pathway in relation to high density lipoprotein (HDL) formation remain poorly understood. We have developed a quantitative cell surface biotinylation assay to determine the compartmentalization and trafficking of apoA-I between the plasma membrane (PM) and intracellular compartments (ICCs). Here we report that (125)I-apoA-I exhibited saturable association with the PM and ICCs in baby hamster kidney cells stably overexpressing ABCA1 and in fibroblasts. Read More

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ABCA1-induced cell surface binding sites for ApoA-I.

Arterioscler Thromb Vasc Biol 2007 Jul 3;27(7):1603-9. Epub 2007 May 3.

Division of GI/Nutrition, The Children's Hospital of Philadelphia, University of Pennsylvania School of Medicine, Philadelphia, PA 19104-4318, USA.

Objective: The purpose of this study was to understand the interactions of apoA-I with cells expressing ABCA1.

Methods And Results: The binding of wild-type (WT) and mutant forms of human apoA-I to mouse J774 macrophages was examined. Analysis of total binding at 37 degrees C of 125I-WT apoA-I to the cells and specifically to ABCA1, as determined by covalent cross-linking, revealed saturable high affinity binding in both cases. Read More

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ApoA-I secretion from HepG2 cells: evidence for the secretion of both lipid-poor apoA-I and intracellularly assembled nascent HDL.

J Lipid Res 2002 Jan;43(1):36-44

Section on Comparative Medicine, Department of Pathology, Wake Forest University School of Medicine, Medical Center Blvd., Winston-Salem, NC 27157-1040, USA.

The goal of this study was to determine whether apolipoprotein A-I (apoA-I) is lipidated before secretion by HepG2 cells. ApoA-I was extracted from microsomes after radiolabeling with [(35)S]Met/Cys. After ultracentrifugal flotation, d < 1. Read More

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January 2002

Association of human apolipoprotein E with lipoproteins secreted by transfected McA RH7777 cells.

J Lipid Res 1998 Jul;39(7):1372-81

Department of Pathology, The University of Chicago, IL 60637-1470, USA.

To examine the association of apolipoprotein (apo) E with nascent hepatic lipoproteins we have prepared stable transfectants of the rat hepatoma cell line McA RH7777 expressing the human apoE3 cDNA. When the nascent lipoproteins secreted from control cells were separated on fast protein liquid chromatography (FPLC) columns, rat apoE was detected in the very low density (VLDL) and high density lipoprotein (HDL) fractions, while rat apoA-I was found in the HDL and lipoprotein free fractions. Human apoE was also associated with the VLDL and HDL particles secreted from the transfected McA RH7777 cells. Read More

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Physical and functional association of the major histocompatibility complex class I heavy chain alpha3 domain with the transporter associated with antigen processing.

J Exp Med 1998 Mar;187(6):865-74

Michael Heidelberger Division of Immunology, the Department of Pathology and Kaplan Comprehensive Cancer Center, New York University Medical Center, New York 10016, USA.

CD8+ T lymphocytes recognize antigens as short, MHC class I-associated peptides derived by processing of cytoplasmic proteins. The transporter associated with antigen processing translocates peptides from the cytosol into the ER lumen, where they bind to the nascent class I molecules. To date, the precise location of the class I-TAP interaction site remains unclear. Read More

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TFIIS binds to mouse RNA polymerase I and stimulates transcript elongation and hydrolytic cleavage of nascent rRNA.

Mol Gen Genet 1996 Sep;252(4):412-9

Division of Molecular Biology of the Cell II, German Cancer Research Center, Heidelberg, Germany.

Efficient transcription elongation by RNA polymerase I (Pol I) requires a specific Pol I-associated factor, termed TIF-IC. Here we show that TFIIS, a factor that has previously been shown to promote read-through past many types of blocks to elongation by RNA polymerase II, also enhances Pol I-directed transcription elongation. In a reconstituted transcription system containing purified proteins, TFIIS stimulates Pol I transcription by increasing the overall rate of RNA chain elongation. Read More

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September 1996
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