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Khan I, Koide A, Zuberi M, Ketavarapu G, Denbaum E, Teng KW, Rhett JM, Spencer-Smith R, Hobbs GA, Camp ER, Koide S, O'Bryan JP. Identification of the nucleotide-free state as a therapeutic vulnerability for inhibition of selected oncogenic RAS mutants. Cell Rep 2022; 38:110322. [PMID: 35139380 PMCID: PMC8936000 DOI: 10.1016/j.celrep.2022.110322] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 11/12/2021] [Accepted: 01/10/2022] [Indexed: 11/16/2022] Open
Abstract
RAS guanosine triphosphatases (GTPases) are mutated in nearly 20% of human tumors, making them an attractive therapeutic target. Following our discovery that nucleotide-free RAS (apo RAS) regulates cell signaling, we selectively target this state as an approach to inhibit RAS function. Here, we describe the R15 monobody that exclusively binds the apo state of all three RAS isoforms in vitro, regardless of the mutation status, and captures RAS in the apo state in cells. R15 inhibits the signaling and transforming activity of a subset of RAS mutants with elevated intrinsic nucleotide exchange rates (i.e., fast exchange mutants). Intracellular expression of R15 reduces the tumor-forming capacity of cancer cell lines driven by select RAS mutants and KRAS(G12D)-mutant patient-derived xenografts (PDXs). Thus, our approach establishes an opportunity to selectively inhibit a subset of RAS mutants by targeting the apo state with drug-like molecules. Khan et al. develop a high-affinity monobody to nucleotide-free RAS that, when expressed intracellularly, inhibits oncogenic RAS-mediated signaling and tumorigenesis. This study reveals the feasibility of targeting the nucleotide-free state to inhibit tumors driven by oncogenic RAS mutants that possess elevated nucleotide exchange activity.
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Affiliation(s)
- Imran Khan
- Department of Cell and Molecular Pharmacology and Experimental Therapeutics, Medical University of South Carolina, Charleston, SC 29425, USA; Hollings Cancer Center, Medical University of South Carolina, Charleston, SC 29425, USA; Ralph H. Johnson VA Medical Center, Charleston, SC 29401, USA; Department of Pharmacology, University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Akiko Koide
- Perlmutter Cancer Center, New York University Langone Health, New York, NY 10016, USA; Department of Medicine, New York University School of Medicine, New York, NY 10016, USA
| | - Mariyam Zuberi
- Department of Cell and Molecular Pharmacology and Experimental Therapeutics, Medical University of South Carolina, Charleston, SC 29425, USA; Hollings Cancer Center, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Gayatri Ketavarapu
- Perlmutter Cancer Center, New York University Langone Health, New York, NY 10016, USA
| | - Eric Denbaum
- Perlmutter Cancer Center, New York University Langone Health, New York, NY 10016, USA
| | - Kai Wen Teng
- Perlmutter Cancer Center, New York University Langone Health, New York, NY 10016, USA
| | - J Matthew Rhett
- Department of Cell and Molecular Pharmacology and Experimental Therapeutics, Medical University of South Carolina, Charleston, SC 29425, USA; Hollings Cancer Center, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Russell Spencer-Smith
- Department of Pharmacology, University of Illinois at Chicago, Chicago, IL 60612, USA
| | - G Aaron Hobbs
- Department of Cell and Molecular Pharmacology and Experimental Therapeutics, Medical University of South Carolina, Charleston, SC 29425, USA; Hollings Cancer Center, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Ernest Ramsay Camp
- Department of Surgery, Medical University of South Carolina, Charleston, SC 29425, USA; Hollings Cancer Center, Medical University of South Carolina, Charleston, SC 29425, USA; Ralph H. Johnson VA Medical Center, Charleston, SC 29401, USA
| | - Shohei Koide
- Perlmutter Cancer Center, New York University Langone Health, New York, NY 10016, USA; Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY 10016, USA.
| | - John P O'Bryan
- Department of Cell and Molecular Pharmacology and Experimental Therapeutics, Medical University of South Carolina, Charleston, SC 29425, USA; Hollings Cancer Center, Medical University of South Carolina, Charleston, SC 29425, USA; Ralph H. Johnson VA Medical Center, Charleston, SC 29401, USA; Department of Pharmacology, University of Illinois at Chicago, Chicago, IL 60612, USA.
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Abstract
RAS proteins represent critical drivers of tumor development and thus are the focus of intense efforts to pharmacologically inhibit these proteins in human cancer. Although recent success has been attained in developing clinically efficacious inhibitors to KRASG12C, there remains a critical need for developing approaches to inhibit additional mutant RAS proteins. A number of anti-RAS biologics have been developed which reveal novel and potentially therapeutically targetable vulnerabilities in oncogenic RAS. This review will discuss the growing field of anti-RAS biologics and potential development of these reagents into new anti-RAS therapies.
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Affiliation(s)
- Michael Whaby
- Department of Cell and Molecular Pharmacology and Experimental Therapeutics, Hollings Cancer Center, Medical University of South Carolina, Charleston, SC, United States
| | - Imran Khan
- Department of Cell and Molecular Pharmacology and Experimental Therapeutics, Hollings Cancer Center, Medical University of South Carolina, Charleston, SC, United States; Ralph H. Johnson VA Medical Center, Charleston, SC, United States
| | - John P O'Bryan
- Department of Cell and Molecular Pharmacology and Experimental Therapeutics, Hollings Cancer Center, Medical University of South Carolina, Charleston, SC, United States; Ralph H. Johnson VA Medical Center, Charleston, SC, United States.
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3
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Kattan WE, Hancock JF. RAS Function in cancer cells: translating membrane biology and biochemistry into new therapeutics. Biochem J 2020; 477:2893-2919. [PMID: 32797215 PMCID: PMC7891675 DOI: 10.1042/bcj20190839] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 07/20/2020] [Accepted: 07/22/2020] [Indexed: 02/07/2023]
Abstract
The three human RAS proteins are mutated and constitutively activated in ∼20% of cancers leading to cell growth and proliferation. For the past three decades, many attempts have been made to inhibit these proteins with little success. Recently; however, multiple methods have emerged to inhibit KRAS, the most prevalently mutated isoform. These methods and the underlying biology will be discussed in this review with a special focus on KRAS-plasma membrane interactions.
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Affiliation(s)
- Walaa E. Kattan
- Department of Integrative Biology and Pharmacology, McGovern Medical School University of Texas Health Science Center at Houston, TX 77030, USA
- The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, TX 77030, USA
| | - John F. Hancock
- Department of Integrative Biology and Pharmacology, McGovern Medical School University of Texas Health Science Center at Houston, TX 77030, USA
- The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, TX 77030, USA
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4
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Abstract
RAS was identified as a human oncogene in the early 1980s and subsequently found to be mutated in nearly 30% of all human cancers. More importantly, RAS plays a central role in driving tumor development and maintenance. Despite decades of effort, there remain no FDA approved drugs that directly inhibit RAS. The prevalence of RAS mutations in cancer and the lack of effective anti-RAS therapies stem from RAS' core role in growth factor signaling, unique structural features, and biochemistry. However, recent advances have brought promising new drugs to clinical trials and shone a ray of hope in the field. Here, we will exposit the details of RAS biology that illustrate its key role in cell signaling and shed light on the difficulties in therapeutically targeting RAS. Furthermore, past and current efforts to develop RAS inhibitors will be discussed in depth.
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Affiliation(s)
- J Matthew Rhett
- Department of Cell and Molecular Pharmacology and Experimental Therapeutics, Hollings Cancer Center, Medical University of South Carolina, Charleston, SC, United States; Ralph H. Johnson VA Medical Center, Charleston, SC, United States
| | - Imran Khan
- Department of Cell and Molecular Pharmacology and Experimental Therapeutics, Hollings Cancer Center, Medical University of South Carolina, Charleston, SC, United States; Ralph H. Johnson VA Medical Center, Charleston, SC, United States
| | - John P O'Bryan
- Department of Cell and Molecular Pharmacology and Experimental Therapeutics, Hollings Cancer Center, Medical University of South Carolina, Charleston, SC, United States; Ralph H. Johnson VA Medical Center, Charleston, SC, United States.
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5
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Chen K, Shang Z, Dai AL, Dai PL. Novel PI3K/Akt/mTOR pathway inhibitors plus radiotherapy: Strategy for non-small cell lung cancer with mutant RAS gene. Life Sci 2020; 255:117816. [PMID: 32454155 DOI: 10.1016/j.lfs.2020.117816] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Revised: 05/07/2020] [Accepted: 05/16/2020] [Indexed: 02/07/2023]
Abstract
Non-small cell lung cancer (NSCLC) with RAS -mutant gene has been the most difficult obstacle to overcome. Over 25% of muted lung adenocarcinomas have RAS mutation. The prognosis of NSCLC patients with RAS-mutant genes is always poor because there is no effective drug to suppress RAS-mutant genes. NSCLC patients with RAS-mutant usually develop resistance to radiotherapy and chemotherapy, which in some cases leads to a 5-10% survival rate for non-small cell lung cancer (NSCLC). As little clinical symptom of NSCLC was presented at its early stages, thus it always brings in disappointing treatment outcome. Currently, NSCLC presents the highest morbidity and mortality all over the world. The combination of PI3K/AKT/mTOR pathway inhibitors with radiotherapy is a novel strategy to improve radiosensitivity and therapeutic outcome of NSCLC with a RAS-mutant gene. There have been many preclinical studies and clinical trials on the effect of PI3K/AKT/mTOR pathway inhibitors combined with radiotherapy in NSCLC with a RAS-mutant gene have been reported in the past years. This review provides current knowledge of the combination of PI3K/Akt/mTOR pathway inhibitors with radiotherapy, which prove to be a significant improvement for the treatment of NSCLC patients with RAS mutations and will benefit NSCLC patients with RAS mutations.
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Affiliation(s)
- Kai Chen
- The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou 325027, China
| | - Zhongjun Shang
- Third Affiliated Hospital of Kunming Medical University, Tumor Hospital of Yunnan Province, Kunming 650118, China
| | - Ai-Lin Dai
- Kunming Medical University Haiyuan School, Kunming 650100, China; Maternal and Child Health and Family Planning Service Center of Wenshan state, 663000, China
| | - Pei-Ling Dai
- Third Affiliated Hospital of Kunming Medical University, Tumor Hospital of Yunnan Province, Kunming 650118, China; Kunming Medical University, Kunming 650100, China.
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Khan I, Rhett JM, O'Bryan JP. Therapeutic targeting of RAS: New hope for drugging the "undruggable". BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2020; 1867:118570. [PMID: 31678118 PMCID: PMC6937383 DOI: 10.1016/j.bbamcr.2019.118570] [Citation(s) in RCA: 72] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 10/01/2019] [Accepted: 10/14/2019] [Indexed: 12/18/2022]
Abstract
RAS is the most frequently mutated oncogene in cancer and a critical driver of oncogenesis. Therapeutic targeting of RAS has been a goal of cancer research for more than 30 years due to its essential role in tumor formation and maintenance. Yet the quest to inhibit this challenging foe has been elusive. Although once considered "undruggable", the struggle to directly inhibit RAS has seen recent success with the development of pharmacological agents that specifically target the KRAS(G12C) mutant protein, which include the first direct RAS inhibitor to gain entry to clinical trials. However, the limited applicability of these inhibitors to G12C-mutant tumors demands further efforts to identify more broadly efficacious RAS inhibitors. Understanding allosteric influences on RAS may open new avenues to inhibit RAS. Here, we provide a brief overview of RAS biology and biochemistry, discuss the allosteric regulation of RAS, and summarize the various approaches to develop RAS inhibitors.
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Affiliation(s)
- Imran Khan
- Department of Cell and Molecular Pharmacology and Experimental Therapeutics, Hollings Cancer Center, Medical University of South Carolina, Charleston, SC 29425, United States of America; Ralph H. Johnson VA Medical Center, Charleston, SC 29401, United States of America
| | - J Matthew Rhett
- Department of Cell and Molecular Pharmacology and Experimental Therapeutics, Hollings Cancer Center, Medical University of South Carolina, Charleston, SC 29425, United States of America; Ralph H. Johnson VA Medical Center, Charleston, SC 29401, United States of America
| | - John P O'Bryan
- Department of Cell and Molecular Pharmacology and Experimental Therapeutics, Hollings Cancer Center, Medical University of South Carolina, Charleston, SC 29425, United States of America; Ralph H. Johnson VA Medical Center, Charleston, SC 29401, United States of America.
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7
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Shah S, Brock EJ, Ji K, Mattingly RR. Ras and Rap1: A tale of two GTPases. Semin Cancer Biol 2018; 54:29-39. [PMID: 29621614 DOI: 10.1016/j.semcancer.2018.03.005] [Citation(s) in RCA: 113] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Revised: 03/16/2018] [Accepted: 03/29/2018] [Indexed: 02/07/2023]
Abstract
Ras oncoproteins play pivotal roles in both the development and maintenance of many tumor types. Unfortunately, these proteins are difficult to directly target using traditional pharmacological strategies, in part due to their lack of obvious binding pockets or allosteric sites. This obstacle has driven a considerable amount of research into pursuing alternative ways to effectively inhibit Ras, examples of which include inducing mislocalization to prevent Ras maturation and inactivating downstream proteins in Ras-driven signaling pathways. Ras proteins are archetypes of a superfamily of small GTPases that play specific roles in the regulation of many cellular processes, including vesicle trafficking, nuclear transport, cytoskeletal rearrangement, and cell cycle progression. Several other superfamily members have also been linked to the control of normal and cancer cell growth and survival. For example, Rap1 has high sequence similarity to Ras, has overlapping binding partners, and has been demonstrated to both oppose and mimic Ras-driven cancer phenotypes. Rap1 plays an important role in cell adhesion and integrin function in a variety of cell types. Mechanistically, Ras and Rap1 cooperate to initiate and sustain ERK signaling, which is activated in many malignancies and is the target of successful therapeutics. Here we review the role activated Rap1 in ERK signaling and other downstream pathways to promote invasion and cell migration and metastasis in various cancer types.
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Affiliation(s)
- Seema Shah
- Program in Cancer Biology, Wayne State University School of Medicine, Detroit, MI 48201, USA
| | - Ethan J Brock
- Program in Cancer Biology, Wayne State University School of Medicine, Detroit, MI 48201, USA
| | - Kyungmin Ji
- Department of Pharmacology, Wayne State University School of Medicine, Detroit, MI 48201, USA
| | - Raymond R Mattingly
- Program in Cancer Biology, Wayne State University School of Medicine, Detroit, MI 48201, USA; Department of Pharmacology, Wayne State University School of Medicine, Detroit, MI 48201, USA.
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8
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Spencer-Smith R, O'Bryan JP. Direct inhibition of RAS: Quest for the Holy Grail? Semin Cancer Biol 2017; 54:138-148. [PMID: 29248537 DOI: 10.1016/j.semcancer.2017.12.005] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Accepted: 12/13/2017] [Indexed: 12/25/2022]
Abstract
RAS GTPases (H-, K-, and N-RAS) are the most frequently mutated oncoprotein family in human cancer. However, the relatively smooth surface architecture of RAS and its picomolar affinity for nucleotide have given rise to the assumption that RAS is an "undruggable" target. Recent advancements in drug screening, molecular modeling, and a greater understanding of RAS function have led to a resurgence in efforts to pharmacologically target this challenging foe. This review focuses on the state of the art of RAS inhibition, the approaches taken to achieve this goal, and the challenges of translating these discoveries into viable therapeutics.
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Affiliation(s)
- Russell Spencer-Smith
- Department of Pharmacology, University of Illinois at Chicago, Chicago, IL, USA; University of Illinois Cancer Center, University of Illinois at Chicago, Chicago, IL, USA; Jesse Brown VA Medical Center, Chicago, IL, USA
| | - John P O'Bryan
- Department of Pharmacology, University of Illinois at Chicago, Chicago, IL, USA; University of Illinois Cancer Center, University of Illinois at Chicago, Chicago, IL, USA; Jesse Brown VA Medical Center, Chicago, IL, USA.
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9
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Van Schaeybroeck S, Kalimutho M, Dunne PD, Carson R, Allen W, Jithesh PV, Redmond KL, Sasazuki T, Shirasawa S, Blayney J, Michieli P, Fenning C, Lenz HJ, Lawler M, Longley DB, Johnston PG. ADAM17-dependent c-MET-STAT3 signaling mediates resistance to MEK inhibitors in KRAS mutant colorectal cancer. Cell Rep 2014; 7:1940-55. [PMID: 24931611 DOI: 10.1016/j.celrep.2014.05.032] [Citation(s) in RCA: 83] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2012] [Revised: 03/01/2014] [Accepted: 05/12/2014] [Indexed: 12/28/2022] Open
Abstract
There are currently no approved targeted therapies for advanced KRAS mutant (KRASMT) colorectal cancer (CRC). Using a unique systems biology approach, we identified JAK1/2-dependent activation of STAT3 as the key mediator of resistance to MEK inhibitors in KRASMT CRC in vitro and in vivo. Further analyses identified acute increases in c-MET activity following treatment with MEK inhibitors in KRASMT CRC models, which was demonstrated to promote JAK1/2-STAT3-mediated resistance. Furthermore, activation of c-MET following MEK inhibition was found to be due to inhibition of the ERK-dependent metalloprotease ADAM17, which normally inhibits c-MET signaling by promoting shedding of its endogenous antagonist, soluble "decoy" MET. Most importantly, pharmacological blockade of this resistance pathway with either c-MET or JAK1/2 inhibitors synergistically increased MEK-inhibitor-induced apoptosis and growth inhibition in vitro and in vivo in KRASMT models, providing clear rationales for the clinical assessment of these combinations in KRASMT CRC patients.
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Affiliation(s)
- Sandra Van Schaeybroeck
- Centre for Cancer Research and Cell Biology, School of Medicine, Dentistry and Biomedical Science, Queen's University Belfast, 97 Lisburn Road, Belfast BT9 7AE, UK
| | - Murugan Kalimutho
- Centre for Cancer Research and Cell Biology, School of Medicine, Dentistry and Biomedical Science, Queen's University Belfast, 97 Lisburn Road, Belfast BT9 7AE, UK
| | - Philip D Dunne
- Centre for Cancer Research and Cell Biology, School of Medicine, Dentistry and Biomedical Science, Queen's University Belfast, 97 Lisburn Road, Belfast BT9 7AE, UK
| | - Robbie Carson
- Centre for Cancer Research and Cell Biology, School of Medicine, Dentistry and Biomedical Science, Queen's University Belfast, 97 Lisburn Road, Belfast BT9 7AE, UK
| | - Wendy Allen
- Centre for Cancer Research and Cell Biology, School of Medicine, Dentistry and Biomedical Science, Queen's University Belfast, 97 Lisburn Road, Belfast BT9 7AE, UK
| | - Puthen V Jithesh
- Centre for Cancer Research and Cell Biology, School of Medicine, Dentistry and Biomedical Science, Queen's University Belfast, 97 Lisburn Road, Belfast BT9 7AE, UK
| | - Keara L Redmond
- Centre for Cancer Research and Cell Biology, School of Medicine, Dentistry and Biomedical Science, Queen's University Belfast, 97 Lisburn Road, Belfast BT9 7AE, UK
| | - Takehiko Sasazuki
- Institute for Advanced Study, Kyushu University, Higashi-ku, Fukuoka 812-8582, Japan
| | - Senji Shirasawa
- Department of Cell Biology, Faculty of Medicine, Fukuoka University, Jonan-Ku, Fukuoka 814-0180, Japan
| | - Jaine Blayney
- Centre for Cancer Research and Cell Biology, School of Medicine, Dentistry and Biomedical Science, Queen's University Belfast, 97 Lisburn Road, Belfast BT9 7AE, UK
| | - Paolo Michieli
- Laboratory of Experimental Therapy, Candiolo Cancer Institute-FPO, IRCCS, Candiolo, Torino 10060, Italy; Department of Oncology, University of Torino Medical School, Candiolo, Torino 10060, Italy
| | - Cathy Fenning
- Centre for Cancer Research and Cell Biology, School of Medicine, Dentistry and Biomedical Science, Queen's University Belfast, 97 Lisburn Road, Belfast BT9 7AE, UK
| | - Heinz-Josef Lenz
- Division of Medical Oncology, University of Southern California/Norris Comprehensive Cancer Center, Keck School of Medicine, Los Angeles, CA 90033, USA
| | - Mark Lawler
- Centre for Cancer Research and Cell Biology, School of Medicine, Dentistry and Biomedical Science, Queen's University Belfast, 97 Lisburn Road, Belfast BT9 7AE, UK
| | - Daniel B Longley
- Centre for Cancer Research and Cell Biology, School of Medicine, Dentistry and Biomedical Science, Queen's University Belfast, 97 Lisburn Road, Belfast BT9 7AE, UK
| | - Patrick G Johnston
- Centre for Cancer Research and Cell Biology, School of Medicine, Dentistry and Biomedical Science, Queen's University Belfast, 97 Lisburn Road, Belfast BT9 7AE, UK.
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Stephen AG, Esposito D, Bagni RK, McCormick F. Dragging ras back in the ring. Cancer Cell 2014; 25:272-81. [PMID: 24651010 DOI: 10.1016/j.ccr.2014.02.017] [Citation(s) in RCA: 610] [Impact Index Per Article: 61.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2014] [Revised: 02/10/2014] [Accepted: 02/21/2014] [Indexed: 12/13/2022]
Abstract
Ras proteins play a major role in human cancers but have not yielded to therapeutic attack. Ras-driven cancers are among the most difficult to treat and often excluded from therapies. The Ras proteins have been termed "undruggable," based on failures from an era in which understanding of signaling transduction, feedback loops, redundancy, tumor heterogeneity, and Ras' oncogenic role was poor. Structures of Ras oncoproteins bound to their effectors or regulators are unsolved, and it is unknown precisely how Ras proteins activate their downstream targets. These knowledge gaps have impaired development of therapeutic strategies. A better understanding of Ras biology and biochemistry, coupled with new ways of targeting undruggable proteins, is likely to lead to new ways of defeating Ras-driven cancers.
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Affiliation(s)
- Andrew G Stephen
- Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, P.O. Box B, Frederick, MD 21702, USA
| | - Dominic Esposito
- Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, P.O. Box B, Frederick, MD 21702, USA
| | - Rachel K Bagni
- Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, P.O. Box B, Frederick, MD 21702, USA
| | - Frank McCormick
- Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, P.O. Box B, Frederick, MD 21702, USA; UCSF Helen Diller Family Comprehensive Cancer Center, Room 371, 1450 3(rd) Street, P.O. Box 589001, San Francisco, CA 94158-9001, USA.
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Abstract
Ras genes are frequently activated in cancer. Attempts to develop drugs that target mutant Ras proteins have, so far, been unsuccessful. Tumors bearing these mutations, therefore, remain among the most difficult to treat. Most efforts to block activated Ras have focused on pathways downstream. Drugs that inhibit Raf kinase have shown clinical benefit in the treatment of malignant melanoma. However, these drugs have failed to show clinical benefit in Ras mutant tumors. It remains unclear to what extent Ras depends on Raf kinase for transforming activity, even though Raf proteins bind directly to Ras and are certainly major effectors of Ras action in normal cells and in development. Furthermore, Raf kinase inhibitors can lead to paradoxical activation of the MAPK pathway. MEK inhibitors block the Ras-MAPK pathway, but often activate the PI3'-kinase, and have shown little clinical benefit as single agents. This activation is mediated by EGF-R and other receptor tyrosine kinases through relief of a negative feedback loop from ERK. Drug combinations that target multiple points within the Ras signaling network are likely to be necessary to achieve substantial clinical benefit. Other effectors may also contribute to Ras signaling and provide a source of targets. In addition, unbiased screens for genes necessary for Ras transformation have revealed new potential targets and have added to our understanding of Ras cancer biology.
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Affiliation(s)
- Stephan Gysin
- UCSF Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, CA, USA
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12
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Abstract
Extensive research on the Ras proteins and their functions in cell physiology over the past 30 years has led to numerous insights that have revealed the involvement of Ras not only in tumorigenesis but also in many developmental disorders. Despite great strides in our understanding of the molecular and cellular mechanisms of action of the Ras proteins, the expanding roster of their downstream effectors and the complexity of the signalling cascades that they regulate indicate that much remains to be learnt.
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Affiliation(s)
- Antoine E. Karnoub
- Whitehead Institute for Biomedical Research and Massachusetts Institute of Technology, Cambridge, Massachusetts 02142, USA
| | - Robert A. Weinberg
- Whitehead Institute for Biomedical Research and Massachusetts Institute of Technology, Cambridge, Massachusetts 02142, USA
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13
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Mildvan AS, Fry DC. NMR studies of the mechanism of enzyme action. ADVANCES IN ENZYMOLOGY AND RELATED AREAS OF MOLECULAR BIOLOGY 2006; 59:241-313. [PMID: 3544711 DOI: 10.1002/9780470123058.ch6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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14
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15
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Use of antipeptide antibodies in molecular and cellular biology. ACTA ACUST UNITED AC 1999. [DOI: 10.1016/s0075-7535(08)70450-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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16
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Deguchi H, Hamano H, Hayashi Y. c-myc, ras p21 and p53 expression in pleomorphic adenoma and its malignant form of the human salivary glands. ACTA PATHOLOGICA JAPONICA 1993; 43:413-22. [PMID: 8396843 DOI: 10.1111/j.1440-1827.1993.tb01152.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Using an immunohistochemical study and an immunoblot analysis, the expression of cellular oncogenes of the human salivary glands such as c-myc, ras p21, and p53 tumor-suppressor gene in pleomorphic adenomas and its malignant form, carcinoma in pleomorphic adenomas was examined to evaluate a differential biological significance, in comparison with that in normal salivary gland tissues. Immunohistochemically, the c-myc product was detected in 42% of the pleomorphic adenomas and in 56% of the carcinomas in pleomorphic adenoma. The ras p21 expression was observed in 24% of pleomorphic adenomas, and in 50% of carcinomas in pleomorphic adenoma. The p53 protein was detected in 18% of the pleomorphic adenomas and in 67% of the carcinomas in pleomorphic adenoma. Although there was no significant difference between the benign and malignant forms for the expression of c-myc, a statistical significance in ras p21 and p53 expression was found between the pleomorphic adenoma and its malignant form (P < 0.05) and P < 0.001, respectively). An immunoblotting assay clearly demonstrated the expression of c-myc and p53 gene products in both the benign and malignant forms of the pleomorphic adenoma, and that of ras p21 in the malignant form. These results indicate that activation of c-myc and ras p21 proto-oncogenes and the involvement of p53 mutation may play important roles in the malignant transformation of salivary gland pleomorphic adenoma.
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Affiliation(s)
- H Deguchi
- Department of Oral Pathology, Tokushima University School of Dentistry, Japan
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17
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Peng Z, Wang W, Wilson S, Schlender K, Trumbly R, Reimann E. Identification of a glycogen synthase phosphatase from yeast Saccharomyces cerevisiae as protein phosphatase 2A. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(18)99108-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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18
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Hasunuma K, Takimoto A. ATP-GTP-BINDING PROTEINS AND ENDOGENOUS ADP-RIBOSYL TRANSFERASE IN Lemna paucicostata 441. Photochem Photobiol 1989. [DOI: 10.1111/j.1751-1097.1989.tb02911.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Abstract
Little is known about the biochemical or functional nature of the proteins encoded by the bcl-2 gene, which undergoes chromosomal translocation in approximately 85% of follicular lymphoma, 20% of diffuse large cell lymphoma and 10% of chronic lymphocytic leukaemia of B cells. Translocation of bcl-2 sequences from chromosome 18 to the JH segment of the immunoglobulin gene at chromosome band 14q32 in B cells results in deregulated expression of this gene, causing high steady state levels of bcl-2 messenger RNA2. DNA sequence data indicate that bcl-2 encodes two proteins by virtue of alternative splicing, designated as Bcl-2 alpha and Bcl-2 beta, with relative molecular masses of 26,000 and 22,000 respectively. Cell fractionation experiments indicate that the bcl-2 alpha gene product is located at the inner surface of the cell membrane, suggesting a possible role in mitogenic signal transduction. We report here that Bcl-2 alpha has GTP-binding activity and a protein sequence that suggests it belongs to the small molecular weight GTP-binding protein (G protein) family.
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Affiliation(s)
- S Haldar
- Fels Institute for Cancer Research and Molecular Biology, Temple University School of Medicine, Philadelphia, Pennsylvania 19140
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20
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Pai EF, Kabsch W, Krengel U, Holmes KC, John J, Wittinghofer A. Structure of the guanine-nucleotide-binding domain of the Ha-ras oncogene product p21 in the triphosphate conformation. Nature 1989; 341:209-14. [PMID: 2476675 DOI: 10.1038/341209a0] [Citation(s) in RCA: 681] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The crystal structure of the guanine-nucleotide-binding domain of p21 (amino acids 1-166) complexed to the guanosine triphosphate analogue guanosine-5'-(beta, gamma-imido)triphosphate (GppNp) has been determined at a resolution of 2.6 A. The topological order of secondary structure elements is the same as that of the guanine-nucleotide-binding domain of bacterial elongation factor EF-Tu. Many interactions between nucleotide and protein have been identified. The effects of point mutations and the conservation of amino-acid sequence in the guanine-nucleotide-binding proteins are discussed.
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Affiliation(s)
- E F Pai
- Max-Planck-Institut für medizinische Forschung, Abteilung Biophysik, Heidelberg, FRG
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21
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John J, Schlichting I, Schiltz E, Rösch P, Wittinghofer A. C-terminal Truncation of p21H Preserves Crucial Kinetic and Structural Properties. J Biol Chem 1989. [DOI: 10.1016/s0021-9258(18)51599-4] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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22
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P21 v-ras inhibits induction of c-myc and c-fos expression by platelet-derived growth factor. Mol Cell Biol 1989. [PMID: 2854191 DOI: 10.1128/mcb.8.12.5080] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The viral oncogene v-ras inhibited the platelet-derived growth factor (PDGF)-induced upregulation of c-myc and c-fos proto-oncogene expression in fibroblast monolayers. These v-ras-containing cells proliferated in the absence of c-myc induction and no longer required PDGF to support growth. Fibroblasts expressing v-ras continued to express the same number of functional PDGF receptors on their surface as uninfected cells, yet the usual induction of transcription of the genes c-myc, c-fos, and JE in response to PDGF stimulation did not occur in the presence of newly introduced v-ras or chronic v-ras gene expression, and synthesis of c-myc protein did not occur. This inhibitory effect on growth factor-mediated induction of cellular proto-oncogenes was specific for PDGF in that induction of the c-myc and c-fos genes by certain other factors was not impaired.
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23
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Robbins SM, Williams JG, Jermyn KA, Spiegelman GB, Weeks G. Growing and developing Dictyostelium cells express different ras genes. Proc Natl Acad Sci U S A 1989; 86:938-42. [PMID: 2644652 PMCID: PMC286594 DOI: 10.1073/pnas.86.3.938] [Citation(s) in RCA: 61] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The expression of ras-related protein in the cellular slime mold Dictyostelium discoideum is developmentally regulated. It was previously reported that Dictyostelium possesses a single ras gene (Ddras) that is maximally expressed during the pseudoplasmodial stage of development. We have isolated a series of cDNA clones derived from a second ras gene, DdrasG. It encodes a protein that is very similar to the protein encoded by Ddras, but in contrast to Ddras, DdrasG is only expressed during growth and early development. Although other eukaryotic organisms possess more than one ras gene, Dictyostelium is thus far unique in expressing different ras genes at different stages of development. In Dictyostelium the two ras proteins may fulfill different functions, with the DdrasG protein playing a role during cell growth and the Ddras protein playing a role in signal transduction during multicellular development.
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Affiliation(s)
- S M Robbins
- Department of Microbiology, University of British Columbia, Vancouver, Canada
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24
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25
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Zullo JN, Faller DV. P21 v-ras inhibits induction of c-myc and c-fos expression by platelet-derived growth factor. Mol Cell Biol 1988; 8:5080-5. [PMID: 2854191 PMCID: PMC365609 DOI: 10.1128/mcb.8.12.5080-5085.1988] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The viral oncogene v-ras inhibited the platelet-derived growth factor (PDGF)-induced upregulation of c-myc and c-fos proto-oncogene expression in fibroblast monolayers. These v-ras-containing cells proliferated in the absence of c-myc induction and no longer required PDGF to support growth. Fibroblasts expressing v-ras continued to express the same number of functional PDGF receptors on their surface as uninfected cells, yet the usual induction of transcription of the genes c-myc, c-fos, and JE in response to PDGF stimulation did not occur in the presence of newly introduced v-ras or chronic v-ras gene expression, and synthesis of c-myc protein did not occur. This inhibitory effect on growth factor-mediated induction of cellular proto-oncogenes was specific for PDGF in that induction of the c-myc and c-fos genes by certain other factors was not impaired.
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Affiliation(s)
- J N Zullo
- Division of Pediatric Hematology, Dana-Farber Cancer Institute, Boston, Massachusetts 02115
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26
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Ohmi N, Hoshino M, Tagaya M, Fukui T, Kawakita M, Hattori S. Affinity labeling of ras oncogene product p21 with guanosine diphospho- and triphosphopyridoxals. J Biol Chem 1988. [DOI: 10.1016/s0021-9258(18)68215-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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27
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Shalitin C, Kenoshi E, Bartal AH. A yeast-derived ras-gene-related protein expressed in human tumor cells. I. Detection by polyclonal antibodies. Cancer Invest 1988; 6:687-94. [PMID: 3072993 DOI: 10.3109/07357908809078036] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Rabbit polyclonal antibodies (pAb) were raised against a yeast ras-related protein YP20 and shown to be immunoreactive with human normal as well as altered Ha-ras and Ki-ras p21 gene products using immunoblotting and immunoprecipitation techniques. The p21 protein revealed by anti-YP20 antibodies comigrates with p21 protein detected by anti-p21 monoclonal antibody (Cetus Diagnostics). These pAbs were tested against a panel of human acetone-fixed tumor cell lines and malignant effusions and nonfixed fresh-frozen tissue sections obtained from cancer patients by the indirect immunofluorescence assay (IFA). Twelve of sixteen (75%) sarcoma and carcinoma cells lines and one fibroblast cell line were stained by the anti-YP20 pAb. The binding occurred most commonly in the cytoplasm. Six of eight fresh-frozen colon and breast cancer tissue sections were immunostained and normal sections from these organs or skin showed only low level of binding to the pAbs. Four of five malignant effusions were distinctively immunostained. These antibodies are suggested to serve as additional probes for assessing the expression of ras gene-related proteins in human malignancy.
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Affiliation(s)
- C Shalitin
- Department of Biology, Technion-Israel Institute of Technology, Haifa
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28
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Abstract
We directly expressed human R-ras 23,000-dalton protein (p23) cDNA in Escherichia coli under the control of the trp promoter. GTP-dependent phosphorylation of a p23 threonine 85 substitution mutant was observed. This result is in direct analogy to the autokinase activity of H-ras and K-ras threonine 59 substitution mutants. Normal p23 protein was detected in the human fibrosarcoma cell line HT1080 by immunoprecipitation with rabbit antibodies raised against an E. coli-expressed R-ras fusion protein. The R-ras p23 protein was found to be 3H labeled in the presence of [9,10(n)-3H]palmitic acid and is associated with the P100 membrane fraction of HT1080 cells. These data suggest that human R-ras p23 has biochemical properties very similar to those of the p21 products of the H-, K-, and N-ras proto-oncogenes. We constructed an R-ras minigene and engineered the expression of normal and mutant alleles from the simian virus 40 early region promoter. Normal and mutant R-ras gene products were authenticated by transient expression in COS-7 cells and immunoprecipitation. The valine 38-substituted R-ras p23 displayed reduced electrophoretic mobility. R-ras p21-like proteins, made by eliminating the first 26 R-ras codons, displayed evident mobility differences between the pro form and mature form, along with a valine 12 substitution-dependent change in electrophoretic mobility. Rat-1 fibroblasts were transfected with normal and mutant R-ras alleles and normal and activated H-ras alleles. Unlike the human T24 bladder oncogene-encoded p21, mutant R-ras alleles do not cause monolayer focus formation or growth in soft agar of rat fibroblasts.
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29
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Ishihara H, Nakagawa H, Ono K, Fukuda A. Antibodies against synthetic carboxy-terminal peptides distinguish H-ras and K-ras oncogene products p21. J Immunol Methods 1987; 103:131-9. [PMID: 3309066 DOI: 10.1016/0022-1759(87)90250-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Synthetic peptides corresponding to the carboxy-terminal region of H-ras, K-ras, and N-ras oncogene product p21 proteins are used to obtain antibodies specific to each ras oncogene product. The synthetic peptides of 32 amino acids are immunogenic in rabbits without being coupled to carriers. Specific antibodies are purified by absorption of the antisera with the other peptides coupled to CH-Sepharose 4B, and antibodies reacting with all three peptides are obtained by affinity chromatography. These findings imply that antibodies specific to each peptide recognize the variable carboxy-terminal region while antibodies reacting with all three peptides recognize the constant region of the carboxy-terminal amino acid sequence of p21 proteins. The affinity-purified antibodies against H-ras and K-ras peptides are shown to react specifically with c-H-ras and v-K-ras p21 proteins expressed in E. coli and eukaryotic cells, respectively. These antibodies may be useful tools to study the functional roles of p21 carboxy-terminal domain and to detect differential expression of the family of ras oncogenes in cancerous tissues. The affinity-purified anti-N-ras peptide antibody, however, fails to react with N-ras p21 in spite of its positive reactivity with the N-ras peptide.
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Affiliation(s)
- H Ishihara
- Basic Research Department, Hoechst Japan Limited, Saitama
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30
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Lowe DG, Goeddel DV. Heterologous expression and characterization of the human R-ras gene product. Mol Cell Biol 1987; 7:2845-56. [PMID: 3313005 PMCID: PMC367902 DOI: 10.1128/mcb.7.8.2845-2856.1987] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
We directly expressed human R-ras 23,000-dalton protein (p23) cDNA in Escherichia coli under the control of the trp promoter. GTP-dependent phosphorylation of a p23 threonine 85 substitution mutant was observed. This result is in direct analogy to the autokinase activity of H-ras and K-ras threonine 59 substitution mutants. Normal p23 protein was detected in the human fibrosarcoma cell line HT1080 by immunoprecipitation with rabbit antibodies raised against an E. coli-expressed R-ras fusion protein. The R-ras p23 protein was found to be 3H labeled in the presence of [9,10(n)-3H]palmitic acid and is associated with the P100 membrane fraction of HT1080 cells. These data suggest that human R-ras p23 has biochemical properties very similar to those of the p21 products of the H-, K-, and N-ras proto-oncogenes. We constructed an R-ras minigene and engineered the expression of normal and mutant alleles from the simian virus 40 early region promoter. Normal and mutant R-ras gene products were authenticated by transient expression in COS-7 cells and immunoprecipitation. The valine 38-substituted R-ras p23 displayed reduced electrophoretic mobility. R-ras p21-like proteins, made by eliminating the first 26 R-ras codons, displayed evident mobility differences between the pro form and mature form, along with a valine 12 substitution-dependent change in electrophoretic mobility. Rat-1 fibroblasts were transfected with normal and mutant R-ras alleles and normal and activated H-ras alleles. Unlike the human T24 bladder oncogene-encoded p21, mutant R-ras alleles do not cause monolayer focus formation or growth in soft agar of rat fibroblasts.
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Affiliation(s)
- D G Lowe
- Department of Molecular Biology, Genentech, Inc., South San Francisco, California 94080
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31
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Meltzer SJ, Ahnen DJ, Battifora H, Yokota J, Cline MJ. Protooncogene abnormalities in colon cancers and adenomatous polyps. Gastroenterology 1987; 92:1174-80. [PMID: 3557013 DOI: 10.1016/s0016-5085(87)91074-2] [Citation(s) in RCA: 53] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
To determine the frequency and clinical significance of oncogene abnormalities in colon cancer, deoxyribonucleic acids from 45 colon carcinomas and 15 benign adenomas were hybridized with 14 different protooncogene probes. Abnormalities of oncogenes were found in 22% of cancers at the time of resection. Amplification of c-myc or c-erbB-2 and allelic deletion of c-ras-Ha or c-myb were the most frequent abnormalities. The presence of altered oncogenes did not correlate with Dukes' stage, tumor progression, or patient survival after resection. One adenoma had an allelic deletion of the c-myb oncogene which was not seen in either the normal colon or an adjacent carcinoma. These data indicate that the spectrum of altered protooncogenes in colon carcinoma is similar to that of other adenocarcinomas, and that unstable oncogenes can be found before overt malignancy develops.
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32
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Mustelin T. GTP dependence of the transduction of mitogenic signals through the T3 complex in T lymphocytes indicates the involvement of a G-protein. FEBS Lett 1987; 213:199-203. [PMID: 3104085 DOI: 10.1016/0014-5793(87)81491-6] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The T3 molecule on the surface membrane of T lymphocytes is involved in the transduction of the proliferation signal generated by an interaction between the antigen receptor and an antigen, to the interior of the T cell. Mitogenic monoclonal antibodies against the T3 molecule and mitogenic lectins induce a rapid (within 5 min) protein synthesis-independent activation of ornithine decarboxylase (ODC) in human T lymphocytes. When T cells are selectively depleted of guanine nucleotides by treatment with mycophenolic acid, the early mitogen-induced activation of ODC is completely inhibited. The inhibition rapidly reverted on the addition of guanine a few minutes before the mitogenic stimulation, and even more rapidly by GTP directly introduced into the T cells by a transient membrane permeabilization. GTP can be substituted for by a non-hydrolyzable GTP analogue, GTP-gamma-S, which also induces ODC activity by itself in human T cells. These results suggest that a G-protein(s) is involved in the transduction of the proliferation signal in human T cells.
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33
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Nakano ET, Rao MM, Perucho M, Inouye M. Expression of the Kirsten ras viral and human proteins in Escherichia coli. J Virol 1987; 61:302-7. [PMID: 3027361 PMCID: PMC253950 DOI: 10.1128/jvi.61.2.302-307.1987] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The expression vectors pINIII-A and pINIII (lpp p5) were used to construct plasmids which direct the synthesis in Escherichia coli of the Kirsten ras viral (v-Ki-ras) and human cellular (c-Ki-ras) oncogene products as fusion proteins containing 9 and 10 extra amino acids, respectively, at their N termini. Authenticity of the bacterially produced proteins was determined by immunoprecipitation and immunoblot analyses with ras-specific monoclonal antibodies. After induction with isopropyl-beta-D-thiogalactopyranoside, the viral protein represented approximately 20% of the total cellular protein. The majority of the protein was found in the postsonication low-speed centrifugation pellet. The synthesized viral protein was active in GTP binding, as judged by autophosphorylation and photoaffinity labeling assays.
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34
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Abstract
We used linker insertion-deletion mutagenesis to study the catalytic domain of the Harvey murine sarcoma virus v-rasH transforming protein, which is closely related to the cellular rasH protein. The mutants displayed a wide range of in vitro biological activity, from those that induced focal transformation of NIH 3T3 cells with approximately the same efficiency as the wild-type v-rasH gene to those that failed to induce any detectable morphologic changes. Correlation of transforming activity with the location of the mutations enabled us to identify three nonoverlapping segments within the catalytic domain that were dispensable for transformation and six other segments that were required for transformation. Segments that were necessary for guanosine nucleotide (GDP) binding corresponded to three of the segments that were essential for transformation; two of the three segments share strong sequence homology with other purine nucleotide-binding proteins. Loss of GDP binding was associated with apparent instability of the protein. Lesions in two of the three other required regions significantly reduced GDP binding, while small lesions in the last required region did not impair GDP binding or membrane localization. We speculate that this latter region interacts with the putative cellular target of ras. The results suggest that transforming ras proteins require membrane localization, guanosine nucleotide binding, and an additional undefined function that may represent interaction with their target.
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35
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Monoclonal antibody Y13-259 recognizes an epitope of the p21 ras molecule not directly involved in the GTP-binding activity of the protein. Mol Cell Biol 1987. [PMID: 2431273 DOI: 10.1128/mcb.6.4.1002] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The p21 products of ras proto-oncogenes are GTP-binding proteins with associated GTPase activity. Recent studies have indicated that ras p21 may be required for the initiation of normal cell DNA synthesis, since microinjection of a monoclonal antibody, Y13-259, blocks serum stimulation of DNA synthesis in quiescent cell cultures (L. S. Mulcahy, M.R. Smith, and D. W. Stacey, Nature [London] 313:241-243, 1985). We localized the structural domain within the p21 molecule recognized by the Y13-259 monoclonal antibody. By analysis of a series of bacterially expressed p21 deletion mutants, the monoclonal antibody was found to interact with a region between positions 70 and 89 in the p21 amino acid sequence. By comparison of the coding sequences of different p21 proteins recognized by this monoclonal antibody, a highly conserved amino acid region between positions 70 and 81 was found to be the most likely site for the epitope detected by the Y13-259 antibody. This monoclonal antibody was further shown not to interfere directly with in vitro biochemical functions of the molecule, including GTP binding, GTPase, and autokinase activities.
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36
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Ostertag W, Stocking C, Johnson GR, Kluge N, Kollek R, Franz T, Hess N. Transforming genes and target cells of murine spleen focus-forming viruses. Adv Cancer Res 1987; 48:193-355. [PMID: 3039810 DOI: 10.1016/s0065-230x(08)60693-4] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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37
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Dascal N. The use of Xenopus oocytes for the study of ion channels. CRC CRITICAL REVIEWS IN BIOCHEMISTRY 1987; 22:317-87. [PMID: 2449311 DOI: 10.3109/10409238709086960] [Citation(s) in RCA: 514] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Recently, in addition to the "traditional" research on meiotic reinitiation and fertilization mechanisms, the oocytes of the African frog Xenopus laevis have been exploited for the study of numerous aspects of ion channel function and regulation, such as the properties of several endogenous voltage-dependent channels and the involvement of second messengers in mediation of neurotransmitter-evoked membrane responses. In addition, injection of these cells with exogenous messenger RNA results in production and functional expression of foreign membranal proteins, including various voltage- and neurotransmitter-operated ion channels originating from brain, heart, and other excitable tissues. This method provides unique opportunities for the study of the structure, function, and regulation of these channels. A multidisciplinary approach is required, involving molecular biology, electrophysiology, biochemistry, pharmacology, and cytology.
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Affiliation(s)
- N Dascal
- Department of Biology, California Institute of Technology, Pasadena
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38
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Abstract
Most human lymphoid malignancies preserve a pattern of gene expression reflecting their proliferative activity and the development level of clonal expansion and maturation arrest. Characteristics of leukemia and other cancer cells frequently considered to reflect aberrant differentiation may more often reflect clonal selection of cell types that are normally infrequent and transitory. The differentiation status of progenitor or mature lymphoid cells influences which genetic elements are at risk of being exploited, via mutation, recombination, or deletion, for clonal advantage. These alterations may frequently arise spontaneously as a consequence of the unique developmental and functional programs of lymphoid cells and have as a major phenotypic consequence the stabilization of transitory cellular phenotypes.
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39
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Hattori S, Yamashita T, Copeland TD, Oroszlan S, Shih TY. Reactivity of a sulfhydryl group of the ras oncogene product p21 modulated by GTP binding. J Biol Chem 1986. [DOI: 10.1016/s0021-9258(18)66910-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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40
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Lacal JC, Aaronson SA. ras p21 deletion mutants and monoclonal antibodies as tools for localization of regions relevant to p21 function. Proc Natl Acad Sci U S A 1986; 83:5400-4. [PMID: 2426696 PMCID: PMC386294 DOI: 10.1073/pnas.83.15.5400] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Deletion mutants of the viral Harvey ras oncogene were generated by removing different lengths of the gene from either the amino or the carboxyl terminus. The deletion mutants, ras p21 expressed in Escherichia coli, yielded proteins of approximately 8, 10, 12, 14, 17, 18, 19, and 20 kDa. These proteins were utilized to identify epitopes recognized by a series of recently generated monoclonal antibodies as well as some previously reported monoclonal antibodies. Monoclonal antibodies that inhibited GTP binding, a major biochemical activity of the p21 protein, recognized two major regions of the protein. These regions were localized from amino acids 5 to 69 and 107 to 164, respectively, and were separated by another stretch from residues 70 to 106, whose antigenic determinants were not directly involved in GTP binding. Thus, the mapping of epitopes within the p21 molecule recognized by monoclonal antibodies has made it possible to localize important functional regions within the ras p21 molecule.
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41
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Willumsen BM, Papageorge AG, Kung HF, Bekesi E, Robins T, Johnsen M, Vass WC, Lowy DR. Mutational analysis of a ras catalytic domain. Mol Cell Biol 1986; 6:2646-54. [PMID: 3023943 PMCID: PMC367821 DOI: 10.1128/mcb.6.7.2646-2654.1986] [Citation(s) in RCA: 82] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
We used linker insertion-deletion mutagenesis to study the catalytic domain of the Harvey murine sarcoma virus v-rasH transforming protein, which is closely related to the cellular rasH protein. The mutants displayed a wide range of in vitro biological activity, from those that induced focal transformation of NIH 3T3 cells with approximately the same efficiency as the wild-type v-rasH gene to those that failed to induce any detectable morphologic changes. Correlation of transforming activity with the location of the mutations enabled us to identify three nonoverlapping segments within the catalytic domain that were dispensable for transformation and six other segments that were required for transformation. Segments that were necessary for guanosine nucleotide (GDP) binding corresponded to three of the segments that were essential for transformation; two of the three segments share strong sequence homology with other purine nucleotide-binding proteins. Loss of GDP binding was associated with apparent instability of the protein. Lesions in two of the three other required regions significantly reduced GDP binding, while small lesions in the last required region did not impair GDP binding or membrane localization. We speculate that this latter region interacts with the putative cellular target of ras. The results suggest that transforming ras proteins require membrane localization, guanosine nucleotide binding, and an additional undefined function that may represent interaction with their target.
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42
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Clanton DJ, Hattori S, Shih TY. Mutations of the ras gene product p21 that abolish guanine nucleotide binding. Proc Natl Acad Sci U S A 1986; 83:5076-80. [PMID: 3014531 PMCID: PMC323893 DOI: 10.1073/pnas.83.14.5076] [Citation(s) in RCA: 74] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
We have constructed several point mutations affecting the GTP-binding site of p21, the ras-encoded protein. Both lysine (116K) and tyrosine (116Y) mutations of asparagine-116, which, by analogy with the crystal structure of elongation factor Tu (EF-Tu), has critical interactions with the guanine base, abolish GTP binding and transforming activities of p21. These activities are retained by proteins with a mutation at position 117 or 118. Both 116K and 116Y mutant p21s, when overproduced in Escherichia coli, are apparently devoid of GTP-binding and autokinase activities. Similarly, the mutant DNAs do not transform NIH 3T3 cells in a focus-forming assay. By cotransfection with pSV-neo, cell clones resistant to the neomycin analog G418 have been isolated. Cells transfected with 116K or 116Y mutant DNA are contact inhibited. In contrast to competent clones, the defective mutants have no detectable phosphorylated p21. The present results suggest that the basic structure of the GTP-binding site is conserved between p21 and EF-Tu and that this binding site is crucial for ras gene function.
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43
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Lacal JC, Aaronson SA. Monoclonal antibody Y13-259 recognizes an epitope of the p21 ras molecule not directly involved in the GTP-binding activity of the protein. Mol Cell Biol 1986; 6:1002-9. [PMID: 2431273 PMCID: PMC367608 DOI: 10.1128/mcb.6.4.1002-1009.1986] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The p21 products of ras proto-oncogenes are GTP-binding proteins with associated GTPase activity. Recent studies have indicated that ras p21 may be required for the initiation of normal cell DNA synthesis, since microinjection of a monoclonal antibody, Y13-259, blocks serum stimulation of DNA synthesis in quiescent cell cultures (L. S. Mulcahy, M.R. Smith, and D. W. Stacey, Nature [London] 313:241-243, 1985). We localized the structural domain within the p21 molecule recognized by the Y13-259 monoclonal antibody. By analysis of a series of bacterially expressed p21 deletion mutants, the monoclonal antibody was found to interact with a region between positions 70 and 89 in the p21 amino acid sequence. By comparison of the coding sequences of different p21 proteins recognized by this monoclonal antibody, a highly conserved amino acid region between positions 70 and 81 was found to be the most likely site for the epitope detected by the Y13-259 antibody. This monoclonal antibody was further shown not to interfere directly with in vitro biochemical functions of the molecule, including GTP binding, GTPase, and autokinase activities.
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44
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Carney WP, Hamer P, Petit D, Wolfe H, Cooper G, Lefebvre M, Rabin H. A monoclonal antibody reactive with an activated ras protein expressing valine at position 12. J Cell Biochem 1986; 32:207-14. [PMID: 3536974 DOI: 10.1002/jcb.240320307] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Activated ras transforming genes have been described in a variety of neoplasms and encode 21,000-Dalton (p21) proteins with amino acid substitutions at positions 12, 13, and 61. In this report we describe a monoclonal antibody designated DWP that reacts specifically with synthetic dodecapeptides containing valine at position 12, to a lesser extent with peptides containing cysteine at position 12 and not with peptides containing glycine, arginine, serine, aspartic acid, glutamic acid or alanine at the same position. Western blot and immunoperoxidase studies showed that DWP specifically reacts with activated rasH or rasK proteins in NIH cells transformed by DNA from the human carcinoma cells that encode valine at position 12. DWP did not react with normal p21s encoding glycine at position 12, nor with activated p21s encoding aspartic acid, glutamic acid, arginine, serine, or cysteine at position 12. A survey of human tumor cell lines demonstrated that DWP reacted with the human bladder carcinoma cell line T24 but not with human tumor cell lines previously shown to contain other activating mutations at positions 12 or 61. DWP and perhaps additional antibodies that specifically react with alterations at positions 12 or 61 of the ras protein may be valuable in determining the presence and frequency of activated ras proteins in human malignancy.
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Jurnak F. Structure of the GDP domain of EF-Tu and location of the amino acids homologous to ras oncogene proteins. Science 1985; 230:32-6. [PMID: 3898365 DOI: 10.1126/science.3898365] [Citation(s) in RCA: 552] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
A 2.7 angstrom resolution x-ray diffraction analysis of a trypsin-modified form of the Escherichia coli elongation factor Tu reveals that the GDP-binding domain has a structure similar to that of other nucleotide-binding proteins. The GDP ligand is located at the COOH-terminal end of the beta sheet and is linked to the protein via a Mg2+ ion salt bridge. The location of the guanine ring is unusual; the purine ring is located on the outer edge of the domain, not deep within a hydrophobic pocket. The amino acids from Pro10 to Arg44 and from Gly59 to Glu190 have been assigned to the electron density with computer graphic techniques, and the resulting model is consistent with all known biochemical data. An analysis of the structure reveals that four regions of the amino acid sequence that are homologous with the family of ras oncogene proteins, termed p21, are located in the vicinity of the GDP-binding site, and most of the invariant amino acids shared by the proteins interact directly with the GDP ligand.
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McCormick F, Clark BF, la Cour TF, Kjeldgaard M, Norskov-Lauritsen L, Nyborg J. A model for the tertiary structure of p21, the product of the ras oncogene. Science 1985; 230:78-82. [PMID: 3898366 DOI: 10.1126/science.3898366] [Citation(s) in RCA: 230] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
A model was developed for the structure of p21, the protein with a molecular weight of 21,000 that is produced by the ras genes. This model predicts that p21 consists of a central core of beta-sheet structure, connected by loops and alpha helices. Four of these loops comprise the guanine nucleotide binding site. The phosphoryl binding region is made up of amino acid sequences from 10 to 16 and from 57 to 63 of p21. The latter sequence may contain a site for magnesium binding. Amino acids defining guanine specificity are Asn-116 and Asp-119, and sequences around amino acid 145 may contribute to guanine binding. The model makes it possible to visualize how oncogenic mutations of p21 affect interaction with guanine nucleotides.
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