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Jaipuria G, Shet D, Malik S, Swain M, Atreya HS, Galea CA, Slomiany MG, Rosenzweig SA, Forbes BE, Norton RS, Mondal S. IGF-dependent dynamic modulation of a protease cleavage site in the intrinsically disordered linker domain of human IGFBP2. Proteins 2022; 90:1732-1743. [PMID: 35443068 PMCID: PMC9357107 DOI: 10.1002/prot.26350] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 03/02/2022] [Accepted: 03/22/2022] [Indexed: 12/29/2022]
Abstract
Functional regulation via conformational dynamics is well known in structured proteins but less well characterized in intrinsically disordered proteins and their complexes. Using NMR spectroscopy, we have identified a dynamic regulatory mechanism in the human insulin-like growth factor (IGF) system involving the central, intrinsically disordered linker domain of human IGF-binding protein-2 (hIGFBP2). The bioavailability of IGFs is regulated by the proteolysis of IGF-binding proteins. In the case of hIGFBP2, the linker domain (L-hIGFBP2) retains its intrinsic disorder upon binding IGF-1, but its dynamics are significantly altered, both in the IGF binding region and distantly located protease cleavage sites. The increase in flexibility of the linker domain upon IGF-1 binding may explain the IGF-dependent modulation of proteolysis of IGFBP2 in this domain. As IGF homeostasis is important for cell growth and function, and its dysregulation is a key contributor to several cancers, our findings open up new avenues for the design of IGFBP analogs inhibiting IGF-dependent tumors.
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Affiliation(s)
- Garima Jaipuria
- NMR Research Centre, Indian Institute of Science, Bangalore-560012, India
| | - Divya Shet
- NMR Research Centre, Indian Institute of Science, Bangalore-560012, India,Nanobiophysics lab, Raman Research Institute, Sadashivnagar, Bangalore-80, India
| | - Shahid Malik
- NMR Research Centre, Indian Institute of Science, Bangalore-560012, India
| | - Monalisa Swain
- NMR Research Centre, Indian Institute of Science, Bangalore-560012, India,Frederick National Laboratory for Cancer Research, Maryland-21701, USA
| | | | - Charles A. Galea
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Parkville 3052, Australia
| | - Mark G. Slomiany
- Department of Cell and Molecular Pharmacology, Medical University of South Carolina, Charleston SC 29425, USA
| | - Steven A. Rosenzweig
- Department of Cell and Molecular Pharmacology, Medical University of South Carolina, Charleston SC 29425, USA
| | - Briony E. Forbes
- Flinders Health and Medical Research Institute, Flinders University, SA 5042, Australia
| | - Raymond S. Norton
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Parkville 3052, Australia,ARC Centre for Fragment-Based Design, Monash University, Parkville 3052, Australia
| | - Somnath Mondal
- NMR Research Centre, Indian Institute of Science, Bangalore-560012, India,Univ. Bordeaux, Institut Européen de Chimie et Biologie and INSERM U1212, ARNA Laboratory, 2 rue Robert Escarpit, 33607 Pessac Cedex, Bordeaux, France
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Liang J, Tong P, Zhao W, Li Y, Zhang L, Xia Y, Yu Y. The REST gene signature predicts drug sensitivity in neuroblastoma cell lines and is significantly associated with neuroblastoma tumor stage. Int J Mol Sci 2014; 15:11220-33. [PMID: 24968265 PMCID: PMC4139778 DOI: 10.3390/ijms150711220] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2014] [Revised: 05/30/2014] [Accepted: 06/03/2014] [Indexed: 11/16/2022] Open
Abstract
Neuroblastoma is the most common and deadly solid tumor in children, and there is currently no effective treatment available for neuroblastoma patients. The repressor element-1 silencing transcription (REST) factor has been found to play important roles in the regulation of neural differentiation and tumorigenesis. Recently, a REST signature consisting of downstream targets of REST has been reported to have clinical relevance in both breast cancer and glioblastoma. However it remains unclear how the REST signature works in neuroblastoma. Publicly available datasets were mined and bioinformatic approaches were used to investigate the utility of the REST signature in neuroblastoma with both preclinical and real patient data. The REST signature was found to be associated with drug sensitivity in neuroblastoma cell lines. Further, neuroblastoma patients with enhanced REST activity are significantly associated with higher clinical stages. Loss of heterozygosity on chromosome 11q23, which occurs in a large subset of high-risk neuroblastomas, tends to be correlated with high REST activity, with marginal significance. In conclusion, the REST signature has important implications for targeted therapy, and it is a prognostic factor in neuroblastoma patients.
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Affiliation(s)
- Jianfeng Liang
- Department of Neurosurgery, China-Japan Friendship Hospital, Beijing 100029, China.
| | - Pan Tong
- Department of Bioinformatics and Computational Biology, University of Texas M.D. Anderson Cancer Center, Houston, TX 77030, USA.
| | - Wanni Zhao
- Department of General Surgery, Jinan Central Hospital, Jinan 250013, China.
| | - Yaqiao Li
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA.
| | - Li Zhang
- Department of Neurosurgery, China-Japan Friendship Hospital, Beijing 100029, China.
| | - Ying Xia
- The Vivan L. Smith Department of Neurosurgery, The University of Texas Medical School at Houston, Houston, TX 77030, USA.
| | - Yanbing Yu
- Department of Neurosurgery, China-Japan Friendship Hospital, Beijing 100029, China.
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Hjortebjerg R, Flyvbjerg A, Frystyk J. Insulin growth factor binding proteins as therapeutic targets in type 2 diabetes. Expert Opin Ther Targets 2013; 18:209-24. [PMID: 24261835 DOI: 10.1517/14728222.2014.858698] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
INTRODUCTION The signaling pathways of the insulin-like growth factors (IGFs) have been implicated in the aetiology of type 2 diabetes (T2D) and a number of therapeutic modalities aiming at the IGF-axis have been considered. Administration of IGF-I has been reported to improve insulin sensitivity in healthy subjects and patients with T2D. In recent years, the IGF binding proteins (IGFBPs) have also been associated with metabolic disorders, prompting the idea that IGFBPs play important roles in the pathogenesis of T2D. Thus, by virtue of their role in the regulation of IGF effects, the IGFBPs have emerged as potential biomarkers and therapeutic targets in metabolic syndromes and T2D. AREAS COVERED The article provides an overview on recent findings in clinical and experimental IGFBP-research and addresses the studies that have investigated the potentials of the IGFBPs as therapeutic targets in T2D. EXPERT OPINION There is plenty of therapeutic promise within the IGF system, but further understanding of the IGFs in T2D is necessary to avoid off-target effects. Strong evidence supports the use of IGFBPs as therapeutic targets in the treatment of T2D, and it is not difficult to foresee the use of IGFBPs as part of a combination therapy alongside other anti-diabetic drugs.
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Affiliation(s)
- Rikke Hjortebjerg
- Aarhus University, Department of Clinical Medicine, Medical Research Laboratory, Faculty of Health , DK-8000 Aarhus C , Denmark
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Forbes BE, McCarthy P, Norton RS. Insulin-like growth factor binding proteins: a structural perspective. Front Endocrinol (Lausanne) 2012; 3:38. [PMID: 22654863 PMCID: PMC3356058 DOI: 10.3389/fendo.2012.00038] [Citation(s) in RCA: 120] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/02/2012] [Accepted: 02/16/2012] [Indexed: 11/13/2022] Open
Abstract
Insulin-like growth factor binding proteins (IGFBP-1 to -6) bind insulin-like growth factors-I and -II (IGF-I and IGF-II) with high affinity. These binding proteins maintain IGFs in the circulation and direct them to target tissues, where they promote cell growth, proliferation, differentiation, and survival via the type 1 IGF receptor. IGFBPs also interact with many other molecules, which not only influence their modulation of IGF action but also mediate IGF-independent activities that regulate processes such as cell migration and apoptosis by modulating gene transcription. IGFBPs-1 to -6 are structurally similar proteins consisting of three distinct domains, N-terminal, linker, and C-terminal. There have been major advances in our understanding of IGFBP structure in the last decade and a half. While there is still no structure of an intact IGFBP, several structures of individual N- and C-domains have been solved. The structure of a complex of N-BP-4:IGF-I:C-BP-4 has also been solved, providing a detailed picture of the structural features of the IGF binding site and the mechanism of binding. Structural studies have also identified features important for interaction with extracellular matrix components and integrins. This review summarizes structural studies reported so far and highlights features important for binding not only IGF but also other partners. We also highlight future directions in which structural studies will add to our knowledge of the role played by the IGFBP family in normal growth and development, as well as in disease.
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Affiliation(s)
- Briony E Forbes
- The School of Molecular and Biomedical Science, The University of Adelaide Adelaide, SA, Australia
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