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Martelly W, Fellows B, Senior K, Marlowe T, Sharma S. Identification of a noncanonical RNA binding domain in the U2 snRNP protein SF3A1. RNA 2019; 25:1509-1521. [PMID: 31383795 PMCID: PMC6795144 DOI: 10.1261/rna.072256.119] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Accepted: 07/31/2019] [Indexed: 06/10/2023]
Abstract
During splicing of pre-mRNA, 5' and 3' splice sites are brought within proximity by interactions between the pre-mRNA bound U1 and U2 snRNPs, followed by recruitment of the tri-snRNP for assembly of the mature spliceosome. Previously, we identified an interaction between the U2 snRNP-specific protein SF3A1 and the stem-loop 4 (SL4) of the U1 snRNA that occurs during the early steps of spliceosome assembly. Although harboring many annotated domains, SF3A1 lacks a canonical RNA binding domain. To identify the U1-SL4 binding region in SF3A1, we expressed amino- and carboxy-terminal deletion constructs using a HeLa cell-based cell free expression system. UV-crosslinking of the truncated proteins with 32P-U1-SL4 RNA identified the carboxy-terminal ubiquitin-like (UBL) domain of SF3A1 as the RNA binding region. Characterization of the interaction between SF3A1-UBL and U1-SL4 by electrophoretic mobility shift assay and surface plasmon resonance determined high binding affinity (KD = ∼97 nM), and revealed the double-stranded G-C rich stem of U1-SL4 as an important feature for binding to the UBL domain. Further, mutations of two conserved tyrosine residues, Y772 and Y773, were found to cause a two- and fivefold decrease in the binding affinity for U1-SL4, respectively. Finally, we found that SF3A1-UBL can specifically pull down the U1 snRNP from HeLa nuclear extract, demonstrating its capacity to bind U1-SL4 in the context of the intact snRNP. Thus, the data show that the UBL domain of SF3A1 can function as an RNA binding domain and that mutations in this region may interfere with U1-SL4 binding.
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Affiliation(s)
- William Martelly
- Department of Basic Medical Sciences, University of Arizona, College of Medicine-Phoenix, Phoenix, Arizona 85004, USA
- School of Life Sciences, Arizona State University, Tempe, Arizona 85287, USA
| | - Bernice Fellows
- Department of Basic Medical Sciences, University of Arizona, College of Medicine-Phoenix, Phoenix, Arizona 85004, USA
| | - Kristen Senior
- Department of Basic Medical Sciences, University of Arizona, College of Medicine-Phoenix, Phoenix, Arizona 85004, USA
| | - Tim Marlowe
- Molecular Analysis Core, University of Arizona, College of Medicine-Phoenix, Phoenix, Arizona 85004, USA
| | - Shalini Sharma
- Department of Basic Medical Sciences, University of Arizona, College of Medicine-Phoenix, Phoenix, Arizona 85004, USA
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Kissick DJ, Martin-Garcia JM, Hu H, Venugopalan N, Xu S, Corcoran S, Ferguson D, Hilgart MC, Makarov O, Xu Q, Ogata C, Stepanov S, Thifault D, Marlowe T, Alvarado C, Zacks M, Cance W, Fromme P, Fischetti RF. Improvements in serial crystallography capabilities at GM/CA. Acta Crystallogr A Found Adv 2019. [DOI: 10.1107/s010876731909562x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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Kumar S, Yadav N, Marlowe T, Chaudhary A, Wang J, O'Malley J, Boland P, Jayanthi S, Kumar TKS, Yadava N, Chandra D. Abstract 3058: Oxidative phosphorylation-dependent regulation of cancer cell apoptosis in response to anticancer agents. Cancer Res 2015. [DOI: 10.1158/1538-7445.am2015-3058] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Although cancer cells develop resistance to multiple types of anticancer agents, whether they adopt similar or differential mechanisms to evade cell death in response to a broad spectrum of cancer therapeutics is not fully defined. We show differential sensitivity, caspase activation, and cytokines/chemokines release in response to multiple anticancer agents. We demonstrated that DNA-damaging agents (etoposide and doxorubicin), ER stressor (thapsigargin), and histone deacetylase inhibitor (apicidin) target oxidative phosphorylation (OXPHOS) for apoptosis induction, whereas other anticancer agents including staurosporine, taxol, and sorafenib induced apoptosis in OXPHOS-independent manner. DNA-damaging agents induced mitochondrial biogenesis accompanied by increased production of cellular and mitochondrial ROS. Mitochondrial biogenesis upregulated both mitochondrial protein-folding machinery and unfolded protein response. Induction of mitochondrial biogenesis occurred in a caspase activation-independent mechanism but was reduced by autophagy inhibition and p53-deficiency. Abrogation of complex-I blocked DNA damage-induced caspase activation, whereas inhibition of complex II or gross complexes did not modulate the caspase activity. Interestingly, DNA damaging agent doxorubicin showed strong binding to mitochondria, which was disrupted upon OXPHOS complex I-deficiency but not by OXPHOS complex II-deficiency. Thapsigargin-induced caspase activation was reduced upon abrogation of complex-I or gross-complexes whereas a reverse trend was observed with apicidin. Together, our findings define the specific targets of apoptosis induction in response to a broad range of anticancer therapeutics, which provide a new strategy for differential mitochondrial targeting for cancer therapy.
Citation Format: Sandeep Kumar, Neelu Yadav, Tim Marlowe, Ajay Chaudhary, Jianmin Wang, Jordan O'Malley, Patrick Boland, Srinivas Jayanthi, Thallapuranam Krishnaswamy Suresh Kumar, Nagendra Yadava, Dhyan Chandra. Oxidative phosphorylation-dependent regulation of cancer cell apoptosis in response to anticancer agents. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3058. doi:10.1158/1538-7445.AM2015-3058
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McGuire TF, Qian Y, Blaskovich MA, Fossum RD, Sun J, Marlowe T, Corey SJ, Wathen SP, Vogt A, Hamilton AD. CAAX peptidomimetic FTI-244 decreases platelet-derived growth factor receptor tyrosine phosphorylation levels and inhibits stimulation of phosphatidylinositol 3-kinase but not mitogen-activated protein kinase. Biochem Biophys Res Commun 1995; 214:295-303. [PMID: 7669049 DOI: 10.1006/bbrc.1995.2287] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Cysteine farnesylation of the Ras carboxyl terminal tetrapeptide CAAX motif (where C = cysteine, A = leucine, isoleucine, or valine, and X = methionine or serine) is required for Ras biological activity. In this report, we describe the effects of inhibitors of farnesyltransferase (FTase), the enzyme responsible for this lipid modification, on platelet-derived growth factor (PDGF) signaling in NIH-3T3 cells. In vitro, the CAAX peptidomimetic FTI-232 exhibits potent inhibition of FTase activity (IC50 = 150 nM) and its carboxyl-methylated counterpart, FTI-244, inhibits Ras processing in vivo. Treatment of NIH-3T3 cells with FTI-244 inhibits PDGF-induced DNA synthesis but not stimulation of mitogen-activated protein kinase (MAPK). However, FTI-244 significantly reduces PDGF-induced tyrosine phosphorylation levels of PDGF receptor (PDGFR) as well as its association with, and activation of, phosphatidylinositol-3-kinase (PI-3-K), a key enzyme in PDGF-induced mitogenesis.
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Affiliation(s)
- T F McGuire
- University of Pittsburgh, School of Medicine, Department of Pharmacology, Pennsylvania 15261, USA
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