1
|
Wang R, Su D, Liu Y, Huang H, Qiu J, Cao Z, Yang G, Chen H, Luo W, Tao J, Weng G, Zhang T. The NF-κB/NUAK2 signaling axis regulates pancreatic cancer progression by targeting SMAD2/3. iScience 2024; 27:109406. [PMID: 38510132 PMCID: PMC10951638 DOI: 10.1016/j.isci.2024.109406] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Revised: 01/13/2024] [Accepted: 02/29/2024] [Indexed: 03/22/2024] Open
Abstract
Nuclear factor kappa B (NF-κB) plays a pivotal role in the development of pancreatic cancer, and its phosphorylation has previously been linked to the regulation of NUAK2. However, the regulatory connection between NF-κB and NUAK2, as well as NUAK2's role in pancreatic cancer, remains unclear. In this study, we observed that inhibiting NUAK2 impeded the proliferation, migration, and invasion of pancreatic cancer cells while triggering apoptosis. NUAK2 overexpression partially resisted apoptosis and reversed the inhibitory effects of the NF-κB inhibitor. NF-κB transcriptionally regulated NUAK2 transcription by binding to the promoter region of NUAK2. Mechanistically, NUAK2 knockdown remarkably reduced the expression levels of p-SMAD2/3 and SMAD2/3, resulting in decreased nuclear translocation of SMAD4. In SMAD4-negative cells, NUAK2 knockdown impacted FAK signaling by downregulating SMAD2/3. Moreover, NUAK2 knockdown heightened the sensitivity of pancreatic cancer cells to gemcitabine, suggesting that NUAK2 inhibitors could be a promising strategy for pancreatic cancer treatment.
Collapse
Affiliation(s)
- Ruobing Wang
- Department of General Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China
| | - Dan Su
- Department of General Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China
| | - Yueze Liu
- Department of General Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China
| | - Hua Huang
- Department of General Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China
| | - Jiangdong Qiu
- Department of General Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China
| | - Zhe Cao
- Department of General Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China
| | - Gang Yang
- Department of General Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China
| | - Hao Chen
- Department of General Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China
| | - Wenhao Luo
- Department of General Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China
| | - Jinxin Tao
- Department of General Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China
| | - Guihu Weng
- Department of General Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China
| | - Taiping Zhang
- Department of General Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China
- Clinical Immunology Center, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China
| |
Collapse
|
2
|
Su D, Ding C, Qiu J, Yang G, Wang R, Liu Y, Tao J, Luo W, Weng G, Zhang T. Ribosome profiling: a powerful tool in oncological research. Biomark Res 2024; 12:11. [PMID: 38273337 PMCID: PMC10809610 DOI: 10.1186/s40364-024-00562-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2023] [Accepted: 01/12/2024] [Indexed: 01/27/2024] Open
Abstract
Neoplastic cells need to adapt their gene expression pattern to survive in an ever-changing or unfavorable tumor microenvironment. Protein synthesis (or mRNA translation), an essential part of gene expression, is dysregulated in cancer. The emergence of distinct translatomic technologies has revolutionized oncological studies to elucidate translational regulatory mechanisms. Ribosome profiling can provide adequate information on diverse aspects of translation by aiding in quantitatively analyzing the intensity of translating ribosome-protected fragments. Here, we review the primary currently used translatomics techniques and highlight their advantages and disadvantages as tools for translatomics studies. Subsequently, we clarified the areas in which ribosome profiling could be applied to better understand translational control. Finally, we summarized the latest advances in cancer studies using ribosome profiling to highlight the extensive application of this powerful and promising translatomic tool.
Collapse
Affiliation(s)
- Dan Su
- General Surgery Department, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100730, P.R. China
- Key Laboratory of Research in Pancreatic Tumor, Chinese Academy of Medical Sciences, Beijing, 100023, P.R. China
- National Science and Technology Key Infrastructure on Translational Medicine in Peking Union Medical College Hospital, Beijing, 100023, P.R. China
| | - Chen Ding
- General Surgery Department, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100730, P.R. China
- National Science and Technology Key Infrastructure on Translational Medicine in Peking Union Medical College Hospital, Beijing, 100023, P.R. China
| | - Jiangdong Qiu
- General Surgery Department, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100730, P.R. China
- Key Laboratory of Research in Pancreatic Tumor, Chinese Academy of Medical Sciences, Beijing, 100023, P.R. China
- National Science and Technology Key Infrastructure on Translational Medicine in Peking Union Medical College Hospital, Beijing, 100023, P.R. China
| | - Gang Yang
- General Surgery Department, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100730, P.R. China
- Key Laboratory of Research in Pancreatic Tumor, Chinese Academy of Medical Sciences, Beijing, 100023, P.R. China
- National Science and Technology Key Infrastructure on Translational Medicine in Peking Union Medical College Hospital, Beijing, 100023, P.R. China
| | - Ruobing Wang
- General Surgery Department, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100730, P.R. China
- Key Laboratory of Research in Pancreatic Tumor, Chinese Academy of Medical Sciences, Beijing, 100023, P.R. China
- National Science and Technology Key Infrastructure on Translational Medicine in Peking Union Medical College Hospital, Beijing, 100023, P.R. China
| | - Yueze Liu
- General Surgery Department, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100730, P.R. China
- Key Laboratory of Research in Pancreatic Tumor, Chinese Academy of Medical Sciences, Beijing, 100023, P.R. China
- National Science and Technology Key Infrastructure on Translational Medicine in Peking Union Medical College Hospital, Beijing, 100023, P.R. China
| | - Jinxin Tao
- General Surgery Department, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100730, P.R. China
- Key Laboratory of Research in Pancreatic Tumor, Chinese Academy of Medical Sciences, Beijing, 100023, P.R. China
- National Science and Technology Key Infrastructure on Translational Medicine in Peking Union Medical College Hospital, Beijing, 100023, P.R. China
| | - Wenhao Luo
- General Surgery Department, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100730, P.R. China
- Key Laboratory of Research in Pancreatic Tumor, Chinese Academy of Medical Sciences, Beijing, 100023, P.R. China
- National Science and Technology Key Infrastructure on Translational Medicine in Peking Union Medical College Hospital, Beijing, 100023, P.R. China
| | - Guihu Weng
- Key Laboratory of Research in Pancreatic Tumor, Chinese Academy of Medical Sciences, Beijing, 100023, P.R. China
| | - Taiping Zhang
- General Surgery Department, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100730, P.R. China.
- Key Laboratory of Research in Pancreatic Tumor, Chinese Academy of Medical Sciences, Beijing, 100023, P.R. China.
| |
Collapse
|
3
|
Luo W, Wang J, Chen H, Qiu J, Wang R, Liu Y, Su D, Tao J, Weng G, Ma H, Zhang T. Novel strategies optimize immunotherapy by improving the cytotoxic function of T cells for pancreatic cancer treatment. Cancer Lett 2023; 576:216423. [PMID: 37778682 DOI: 10.1016/j.canlet.2023.216423] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Revised: 09/19/2023] [Accepted: 09/29/2023] [Indexed: 10/03/2023]
Abstract
Pancreatic cancer (PC) is considered highly malignant due to its unsatisfying prognosis and limited response to therapies. Immunotherapy has therefore been developed to harness the antigen-specific properties and cytotoxicity of the immune system, aiming to induce a robust anti-tumor immune response that specifically demolishes PC cells while minimizing lethality in healthy tissue. The activation and augmentation of cytotoxic T cells play a critical role in the initiation and final success of immunotherapy. PC, however, is often immunotherapy resistant due to its intrinsic immunosuppressive tumor microenvironment that consequently hampers effective T cell priming. Emerging therapeutic approaches are orientated to modulate the tumor microenvironment in PC to enhance immune system involvement and heighten T cell efficacy. These novel strategies have shown promising therapeutic effects in the treatment of PC either as standalone approaches or combinatorial with other therapeutic schemes. The objective of this article is to explore innovative approaches to optimize immunotherapy for PC patients through T cell cytotoxic function augmentation.
Collapse
Affiliation(s)
- Wenhao Luo
- Department of General Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100730, China.
| | - Jun Wang
- Department of General Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100730, China
| | - Hao Chen
- Department of General Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100730, China
| | - Jiangdong Qiu
- Department of General Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100730, China
| | - Ruobing Wang
- Department of General Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100730, China
| | - Yueze Liu
- Department of General Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100730, China
| | - Dan Su
- Department of General Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100730, China
| | - Jinxin Tao
- Department of General Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100730, China
| | - Guihu Weng
- Department of General Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100730, China
| | - Haowei Ma
- Clinical Medicine, Capital Medical University, Beijing, China
| | - Taiping Zhang
- Department of General Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100730, China; Clinical Immunology Center, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100730, China.
| |
Collapse
|
4
|
Luo W, Wang J, Chen H, Ye L, Qiu J, Liu Y, Wang R, Weng G, Liu T, Su D, Tao J, Ding C, You L, Zhang T. Epidemiology of pancreatic cancer: New version, new vision. Chin J Cancer Res 2023; 35:438-450. [PMID: 37969957 PMCID: PMC10643340 DOI: 10.21147/j.issn.1000-9604.2023.05.03] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Accepted: 10/16/2023] [Indexed: 11/17/2023] Open
Abstract
Pancreatic cancer (PC) is a devastating malignancy with an extremely high mortality rate and poses significant challenges to healthcare systems worldwide. The prevalence of PC risk factors spiked over the years, leading to a global increase in PC incidence rates. The contribution of different risk factors, however, varied from region to region due to genetic predisposition, environmental, social, and political factors underlying disease prevalence in addition to public health strategies. This comprehensive review aims to provide a thorough analysis of the epidemiology of PC, discussing its incidence, risk factors, screening strategies and socioeconomic burden. We compiled a wide range of seminal studies as well as epidemiological investigations to serve this review as a comprehensive guide for researchers, healthcare professionals, and policymakers keen for a more profound understanding of PC epidemiology. This review highlights the essentiality of persistent research efforts, interdisciplinary collaboration, and public health initiatives to address the expanding burden of this malignancy.
Collapse
Affiliation(s)
- Wenhao Luo
- Department of General Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China
| | - Jun Wang
- Department of General Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China
| | - Hao Chen
- Department of General Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China
| | - Liyuan Ye
- Department of General Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China
| | - Jiangdong Qiu
- Department of General Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China
| | - Yueze Liu
- Department of General Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China
| | - Ruobing Wang
- Department of General Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China
| | - Guihu Weng
- Department of General Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China
| | - Tao Liu
- Department of General Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China
| | - Dan Su
- Department of General Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China
| | - Jinxin Tao
- Department of General Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China
| | - Chen Ding
- Department of General Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China
| | - Lei You
- Department of General Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China
| | - Taiping Zhang
- Department of General Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China
| |
Collapse
|
5
|
Weng G, Tao J, Liu Y, Qiu J, Su D, Wang R, Luo W, Zhang T. Organoid: Bridging the gap between basic research and clinical practice. Cancer Lett 2023; 572:216353. [PMID: 37599000 DOI: 10.1016/j.canlet.2023.216353] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 08/11/2023] [Accepted: 08/17/2023] [Indexed: 08/22/2023]
Abstract
Nowadays, the diagnosis and treatment system of malignant tumors has increasingly tended to be more precise and personalized while the existing tumor models are still unable to fully meet the needs of clinical practice. Notably, the emerging organoid platform has been proven to have huge potential in the field of basic-translational medicine, which is expected to promote a paradigm shift in personalized medicine. Here, given the unique advantages of organoid platform, we mainly explore the prominent role of organoid models in basic research and clinical practice from perspectives of tumor biology, tumorigenic microbes-host interaction, clinical decision-making, and regenerative strategy. In addition, we also put forward some practical suggestions on how to construct a new generation of organoid platform, which is destined to vigorously promote the reform of basic-translational medicine.
Collapse
Affiliation(s)
- Guihu Weng
- Department of General Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, No.1 Shuaifuyuan, Wangfujing Street, Beijing, 100730, China
| | - Jinxin Tao
- Department of General Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, No.1 Shuaifuyuan, Wangfujing Street, Beijing, 100730, China
| | - Yueze Liu
- Department of General Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, No.1 Shuaifuyuan, Wangfujing Street, Beijing, 100730, China
| | - Jiangdong Qiu
- Department of General Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, No.1 Shuaifuyuan, Wangfujing Street, Beijing, 100730, China
| | - Dan Su
- Department of General Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, No.1 Shuaifuyuan, Wangfujing Street, Beijing, 100730, China
| | - Ruobing Wang
- Department of General Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, No.1 Shuaifuyuan, Wangfujing Street, Beijing, 100730, China
| | - Wenhao Luo
- Department of General Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, No.1 Shuaifuyuan, Wangfujing Street, Beijing, 100730, China
| | - Taiping Zhang
- Department of General Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, No.1 Shuaifuyuan, Wangfujing Street, Beijing, 100730, China.
| |
Collapse
|
6
|
Abstract
OBJECTIVE G protein-coupled receptor 119 (GPR119) is predominantly expressed in β cells and intestinal L cells. AR231453 is a selective small-molecular GPR119 agonist that enhances glucose-dependent insulin secretion and glucagon-like peptide 1 (GLP-1) release. We investigated whether AR231453 can directly stimulate β-cell replication and improve islet graft function in diabetic mice. METHODS A total of 100 syngenic C57BL/6 mouse islets were transplanted under the left kidney of each chemically induced diabetic C57BL/6 mouse. Starting from the day of transplantation, these recipients were given bromodeoxyuridine (BrdU) daily with or without AR231453 at 10 mg/kg/d. Islet graft function was monitored by measuring blood glucose levels. At 4 weeks, left nephrectomy was performed to remove the kidney bearing the islet grafts to determine β-cell replication in the islet grafts. Insulin and BrdU immunofluorescence staining was performed to detect replicated β cells. Insulin(+) and BrdU(+) β cells in islet grafts were counted using a confocal microscope. To determine whether AR231453 increases plasma GLP-1 levels, we collected plasma from AR231453 treated mice at 30 minutes after treatment and measured plasma active GLP-1 by enzyme-linked immunosorbent assay. RESULTS Although all recipient mice achieved normoglycemia at 28 days with or without treatment, normoglycemia was achieved in significantly fewer days in AR231453-treated mice. The vehicle-treated mice achieved normoglycemia in 16 ± 6 days, while AR231453-treated mice only required only 8 ± 3 days (P < .01). The percentage of insulin(+) and BrdU(+) β cells in islet grafts was significantly higher in AR231453-treated mice than in vehicle-treated mice. The mean percentage of insulin(+) and BrdU(+) β cells in islet grafts was 21.5% ± 6.9% in AR231453-treated mice and 5.6% ± 3.7% in vehicle-treated mice (P < .01). The plasma active GLP-1 levels were also significantly higher in AR231453-treated mice than in vehicle-treated mice (P < .05). CONCLUSION Our data demonstrate that AR231453, a GPR119 agonist, can stimulate β-cell replication and improve islet graft function.
Collapse
Affiliation(s)
- J Gao
- Department of Surgery and Schulze Diabetes Institute, University of Minnesota, Minneapolis, Minnesota, USA
| | | | | | | | | | | |
Collapse
|
7
|
Gao J, Weng G, Aasarullah A, Lu Y, Holstein M, Deruyter B, OʼBrien TD, Guo Z. Stimulating Beta Cell Replication and Improving Islet Graft Function by a GPR40 and GPR120 Dual Agonist. Transplantation 2012. [DOI: 10.1097/00007890-201211271-01095] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
8
|
Abstract
The crystal structure of soluble functional fragments of adenylyl cyclase complexed with G alpha(s) and forskolin, shows three regions of G alpha(s) in direct contact with adenylyl cyclase. The functions of these three regions are not known. We tested synthetic peptides encoding these regions of G alpha(s) on the activities of full-length adenylyl cyclases 2 and 6. A peptide encoding the Switch II region (amino acids 222-247) stimulated both adenylyl cyclases 2- to 3-fold. Forskolin synergized the stimulation. Addition of peptides in the presence of activated G alpha(s) partially inhibited G alpha(s) stimulation. Corresponding Switch II region peptides from G alpha(q) and G alpha(i) did not stimulate adenylyl cyclase. A peptide encoding the Switch I region (amino acids 199-216) also stimulated AC2 and AC6. The stimulatory effects of the two peptides at saturating concentrations were non-additive. A peptide encoding the third contact region (amino acids 268-286) located in the alpha 3-beta 5 region, inhibits basal, forskolin, and G alpha(s)-stimulated enzymatic activities. Since this region in G alpha(s) interacts with both the central cytoplasmic loop and C-terminal tail of adenylyl cyclases this peptide may be involved in blocking interactions between these two domains. These functional data in conjunction with the available structural information suggest that G alpha(s) activation of adenylyl cyclase is a complex event where the alpha 3-beta 5 loop of G alpha(s) may bring together the central cytoplasmic loop and C-terminal tail of adenylyl cyclase thus allowing the Switch I and Switch II regions to function as signal transfer regions to activate adenylyl cyclase.
Collapse
Affiliation(s)
- Y Chen
- Department of Pharmacology, Mount Sinai School of Medicine, New York, New York 10029, USA
| | | | | | | | | |
Collapse
|
9
|
Buck E, Li J, Chen Y, Weng G, Scarlata S, Iyengar R. Resolution of a signal transfer region from a general binding domain in gbeta for stimulation of phospholipase C-beta2. Science 1999; 283:1332-5. [PMID: 10037604 DOI: 10.1126/science.283.5406.1332] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.2] [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: 11/02/2022]
Abstract
Signaling by guanine nucleotide-binding proteins (G proteins) involves sequential protein-protein interactions. G protein-betagamma subunit (Gbetagamma) interactions with phospholipase C-beta2 (PLC-beta2) were studied to determine if all Gbeta contacts are required for signaling. A peptide encoding Gbeta amino acid residues 86 to 105 stimulated PLC-beta2. Six residues (96 to 101) within this sequence could transfer signals and thus constitute a core signal transfer region. Another peptide, encoding Gbeta amino acid residues 115 to 135, did not substantially stimulate PLC-beta2 by itself but inhibited Gbetagamma stimulation, indicating that residues 115 to 135 constitute a general binding domain. Resolution of signal transfer regions from general binding domains indicates that all protein-protein contacts are not required for signal transfer and that it may be feasible to synthesize agonists and antagonists that regulate intracellular signal flow.
Collapse
Affiliation(s)
- E Buck
- Department of Pharmacology, Mount Sinai School of Medicine, New York, NY 10029, USA
| | | | | | | | | | | |
Collapse
|
10
|
Warner DR, Weng G, Yu S, Matalon R, Weinstein LS. A novel mutation in the switch 3 region of Gsalpha in a patient with Albright hereditary osteodystrophy impairs GDP binding and receptor activation. J Biol Chem 1998; 273:23976-83. [PMID: 9727013 DOI: 10.1074/jbc.273.37.23976] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Albright hereditary osteodystrophy (AHO), a disorder characterized by skeletal abnormalities and obesity, is associated with heterozygous inactivating mutations in the gene for Gsalpha. A novel Gsalpha mutation encoding the substitution of tryptophan for a nonconserved arginine within the switch 3 region (Gsalpha R258W) was identified in an AHO patient. Although reverse transcription-polymerase chain reaction studies demonstrated that mRNA expression from wild type and mutant alleles was similar, Gsalpha expression in erythrocyte membranes from the affected patient was reduced by 50%. A Gsalpha R258W cDNA, as well as one with arginine replaced by alanine (Gsalpha R258A), was generated, and the biochemical properties of in vitro transcription/translation products were examined. When reconstituted with cyc- membranes, both mutant proteins were able to stimulate adenylyl cyclase normally in the presence of guanosine- 5'-O-(3-thiotriphosphate) (GTPgammaS) but had decreased ability in the presence of isoproterenol or AlF4- (a mixture of 10 microM AlCl3 and 10 mM NaF). The ability of each mutant to bind and be activated by GTPgammaS or AlF4- was assessed by trypsin protection assays. Both mutants were protected normally by GTPgammaS but showed reduced protection in the presence of AlF4-. The addition of excess GDP (2 mM) was able to rescue the ability of AlF4- to protect the mutants, suggesting that they might have reduced affinity for GDP. A Gsalpha R258A mutant purified from Escherichia coli had decreased affinity for GDP and an apparent rate of GDP release that was 10-fold greater than that of wild type Gsalpha. Sucrose density gradient analysis demonstrated that both Gsalpha R258W and Gsalpha R258A were thermolabile at higher temperatures and that denaturation of both mutants was prevented by the presence of 0.1 mM GTPgammaS or 2 mM GDP. The crystal structure of Gsalpha demonstrates that Arg258 interacts with a conserved residue in the helical domain (Gln170). Arg258 substitutions would be predicted to open the cleft between the GTPase and helical domains, allowing for increased GDP release in the inactive state, resulting in enhanced thermolability and reduced AlF4--induced adenylyl cyclase stimulation and trypsin protection, since activation by AlF4- requires bound GDP.
Collapse
MESH Headings
- Adenylyl Cyclases/metabolism
- Adult
- Alanine
- Aluminum Compounds/pharmacology
- Amino Acid Sequence
- Arginine
- Base Sequence
- Binding Sites
- Cloning, Molecular
- Erythrocyte Membrane/metabolism
- Escherichia coli
- Exons
- Female
- Fibrous Dysplasia, Polyostotic/genetics
- Fluorides/pharmacology
- GTP-Binding Protein alpha Subunits, Gs/blood
- GTP-Binding Protein alpha Subunits, Gs/chemistry
- GTP-Binding Protein alpha Subunits, Gs/genetics
- Guanosine 5'-O-(3-Thiotriphosphate)/metabolism
- Guanosine Diphosphate/metabolism
- Humans
- Male
- Models, Molecular
- Molecular Sequence Data
- Mutagenesis, Site-Directed
- Point Mutation
- Polymerase Chain Reaction
- Protein Biosynthesis
- Protein Structure, Secondary
- RNA, Messenger/genetics
- Receptors, Cell Surface/metabolism
- Recombinant Proteins/metabolism
- Transcription, Genetic
- Tryptophan
Collapse
Affiliation(s)
- D R Warner
- Membrane Biochemistry Section, Laboratory of Molecular and Cellular Neurobiology, NINDS, National Institutes of Health, Bethesda, Maryland 20892, USA.
| | | | | | | | | |
Collapse
|
11
|
Ford CE, Skiba NP, Bae H, Daaka Y, Reuveny E, Shekter LR, Rosal R, Weng G, Yang CS, Iyengar R, Miller RJ, Jan LY, Lefkowitz RJ, Hamm HE. Molecular basis for interactions of G protein betagamma subunits with effectors. Science 1998; 280:1271-4. [PMID: 9596582 DOI: 10.1126/science.280.5367.1271] [Citation(s) in RCA: 360] [Impact Index Per Article: 13.8] [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: 11/02/2022]
Abstract
Both the alpha and betagamma subunits of heterotrimeric guanine nucleotide-binding proteins (G proteins) communicate signals from receptors to effectors. Gbetagamma subunits can regulate a diverse array of effectors, including ion channels and enzymes. Galpha subunits bound to guanine diphosphate (Galpha-GDP) inhibit signal transduction through Gbetagamma subunits, suggesting a common interface on Gbetagamma subunits for Galpha binding and effector interaction. The molecular basis for interaction of Gbetagamma with effectors was characterized by mutational analysis of Gbeta residues that make contact with Galpha-GDP. Analysis of the ability of these mutants to regulate the activity of calcium and potassium channels, adenylyl cyclase 2, phospholipase C-beta2, and beta-adrenergic receptor kinase revealed the Gbeta residues required for activation of each effector and provides evidence for partially overlapping domains on Gbeta for regulation of these effectors. This organization of interaction regions on Gbeta for different effectors and Galpha explains why subunit dissociation is crucial for signal transmission through Gbetagamma subunits.
Collapse
Affiliation(s)
- C E Ford
- Institute for Neuroscience and Department of Molecular Pharmacology and Biological Chemistry, Northwestern University, Chicago, IL 60611, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
12
|
Chen Y, Harry A, Li J, Smit MJ, Bai X, Magnusson R, Pieroni JP, Weng G, Iyengar R. Adenylyl cyclase 6 is selectively regulated by protein kinase A phosphorylation in a region involved in Galphas stimulation. Proc Natl Acad Sci U S A 1997; 94:14100-4. [PMID: 9391159 PMCID: PMC28439 DOI: 10.1073/pnas.94.25.14100] [Citation(s) in RCA: 109] [Impact Index Per Article: 4.0] [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: 02/05/2023] Open
Abstract
Receptors activate adenylyl cyclases through the Galphas subunit. Previous studies from our laboratory have shown in certain cell types that express adenylyl cyclase 6 (AC6), heterologous desensitization included reduction of the capability of adenylyl cyclases to be stimulated by Galphas. Here we further analyze protein kinase A (PKA) effects on adenylyl cyclases. PKA treatment of recombinant AC6 in insect cell membranes results in a selective loss of stimulation by high (>10 nM) concentrations of Galphas. Similar treatment of AC1 or AC2 did not affect Galphas stimulation. Conversion of Ser-674 in AC6 to an Ala blocks PKA phosphorylation and PKA-mediated loss of Galphas stimulation. A peptide encoding the region 660-682 of AC6 blocks stimulation of AC6 and AC2 by high concentrations of Galphas. Substitution of Ser-674 to Asp in the peptide renders the peptide ineffective, indicating that the region 660-682 of AC6 is involved in regulation of signal transfer from Galphas. This region contains a conserved motif present in most adenylyl cyclases; however, the PKA phosphorylation site is unique to members of the AC6 family. These observations suggest a mechanism of how isoform selective regulatory diversity can be obtained within conserved regions involved in signal communication.
Collapse
Affiliation(s)
- Y Chen
- Department of Pharmacology, Mount Sinai School of Medicine, New York, NY 10029, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
13
|
Abstract
Regulation of adenylyl cyclases 1, 2, and 6 by Galphas was studied. All three mammalian adenylyl cyclases were expressed in insect (Sf9 or Hi-5) cells by baculovirus infection. Membranes containing the different adenylyl cyclases were stimulated by varying concentrations of mutant (Q227L) activated Galphas expressed in reticulocyte lysates. Galphas stimulation of AC1 involved a single site and had an apparent Kact of 0.9 nM. Galphas stimulation of AC2 was best explained by a non-interactive two site model with a "high affinity" site at 0.9 nM and a "low affinity" site at 15 nM. Occupancy of the high affinity site appears to be sufficient for Gbetagamma stimulation of AC2. Galphas stimulation of AC6 was also best explained by a two-site model with a high affinity site at 0. 6-0.8 nM and a low affinity site at 8-22 nM; however, in contrast to AC2, only a model that assumed interactions between the two sites best fit the AC6 data. With 100 microM forskolin, Galphas stimulation of all three adenylyl cyclases showed very similar profiles. Galphas stimulation in the presence of forskolin involved a single site with apparent Kact of 0.1-0.4 nM. These observations indicate a conserved mechanism by which forskolin regulates Galphas coupling to the different adenylyl cyclases. However, there are fundamental differences in the mechanism of Galphas stimulation of the different adenylyl cyclases with AC2 and AC6 having multiple interconvertible sites. These mechanistic differences may provide an explanation for the varied responses by different cells and tissues to hormones that elevate cAMP levels.
Collapse
Affiliation(s)
- A Harry
- Department of Pharmacology, Mount Sinai School of Medicine, New York, New York 10029, USA
| | | | | | | | | |
Collapse
|
14
|
Chen Y, Weng G, Li J, Harry A, Pieroni J, Dingus J, Hildebrandt JD, Guarnieri F, Weinstein H, Iyengar R. A surface on the G protein beta-subunit involved in interactions with adenylyl cyclases. Proc Natl Acad Sci U S A 1997; 94:2711-4. [PMID: 9122261 PMCID: PMC20154 DOI: 10.1073/pnas.94.6.2711] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.5] [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] [Received: 12/04/1996] [Accepted: 12/30/1996] [Indexed: 02/04/2023] Open
Abstract
Receptor activation of heterotrimeric G proteins dissociates G alpha from the G betagamma complex, allowing both to regulate effectors. Little is known about the effector-interaction regions of G betagamma. We had used molecular modeling to dock a peptide encoding the region of residues 956-982 of adenylyl cyclase (AC) 2 onto Gbeta to identify residues on Gbeta that may interact with effectors. Based on predictions from the model, we synthesized peptides encoding sequences of residues 86-105 (Gbeta 86-105) and 115-135 (Gbeta 115-135) from Gbeta. The Gbeta 86-105 peptide inhibited G betagamma stimulation of AC2 and blocked G betagamma inhibition of AC1 and by itself inhibited calmodulin-stimulated AC1, thus displaying partial agonist activity. Substitution of Met-101 with Asn in this peptide resulted in the loss of both the inhibitory and partial agonist activities. Most activities of the Gbeta 115-135 peptide were similar to those of Gbeta 86-105 but Gbeta 115-135 was less efficacious in blocking G betagamma inhibition of AC1. Substitution of Tyr-124 with Val in the Gbeta 115-135 peptide diminished all of its activities. These results identify the region encoded by amino acids 84-143 of Gbeta as a surface that is involved in transmitting signals to effectors.
Collapse
Affiliation(s)
- Y Chen
- Department of Pharmacology, Mount Sinai School of Medicine, New York, NY 10029, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
15
|
Weng G, Li J, Dingus J, Hildebrandt JD, Weinstein H, Iyengar R. Gbeta subunit interacts with a peptide encoding region 956-982 of adenylyl cyclase 2. Cross-linking of the peptide to free Gbetagamma but not the heterotrimer. J Biol Chem 1996; 271:26445-8. [PMID: 8900107 DOI: 10.1074/jbc.271.43.26445] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.6] [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: 02/02/2023] Open
Abstract
The region encoded by amino acids 956-982 of adenylyl cyclase 2 is important for Gbetagamma stimulation. Interactions of a peptide encoding the 956-982 region of adenylyl cyclase 2 (QEHAQEPERQYMHIGTMVEFAYALVGK (QEHA peptide)) with Gbetagamma subunits were studied. QEHA peptide was covalently attached to beta subunit of free Gbetagamma by the cross-linker N-succinimidyl(4-iodoacetyl)aminobenzoate. Cross-linking was proportional to the amount of QEHA peptide added; other control peptides cross-linked minimally. When Go was used, very little cross-linking was observed with GDP and EDTA, but upon activation by guanosine 5'-3-O-(thio)triphosphate and Mg2+, specific cross-linking of the QEHA peptide to Gbeta was observed. We conclude that beta subunits of G proteins contain effector interaction domains that are occluded by Galpha subunits in the heterotrimer. Molecular modeling studies used to dock the QEHA peptide on to Gbeta indicate that amino acids 75-165 of Gbeta may be involved in effector interactions.
Collapse
Affiliation(s)
- G Weng
- Department of Pharmacology, Mount Sinai School of Medicine, City University of New York, New York 10029, USA
| | | | | | | | | | | |
Collapse
|
16
|
Huang L, Deng H, Weng G, Koutalos Y, Ebrey T, Groesbeek M, Lugtenburg J, Tsuda M, Callender RH. A resonance Raman study of the C=N configurations of octopus rhodopsin, bathorhodopsin, and isorhodopsin. Biochemistry 1996; 35:8504-10. [PMID: 8679611 DOI: 10.1021/bi960638g] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [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: 02/01/2023]
Abstract
The resonance Raman spectra of octopus rhodopsin, bathorhodopsin, and isorhodopsin at 120 K have been obtained as well as those of pigments regenerated with isotopically labeled retinals near the C14-C15 bond. Deuteration of the Schiff base nitrogen induces relatively large changes in the C-C stretch region between 1100 and 1300 cm-1, including a large frequency shift of the C14-C15 stretch mode located at 1206-1227 cm-1 in the three octopus species, as revealed by the Raman spectra of their 14,15-(13)C2 derivatives. Such results are different compared to those of the bovine pigments, in which no significant frequency shift of the C14-C15 stretch mode was observed upon Schiff base N deuteration. In an earlier Raman study of a Schiff base model compound which contained only one single bond adjacent to two double bonds, we have found that the stretch mode of this C-C single bond at 1232 cm-1 shifts up by 15 cm-1 and its intensity is also greatly reduced upon Schiff base N deuteration when the C=N configuration is anti [Deng et al., (1994) J. Phys. Chem. 98, 4776-4779]. The same study has also shown that when the C=N configuration is syn, the C-C stretch mode should be at about 1150 cm-1. Since the C14-C15 stretch mode frequency is relatively high in the spectra of octopus rhodopsin and bathorhodopsin (> 1200 cm-1) and since the normal mode pattern near the Schiff base is similar to the model, we suggest that the C=N configuration in these two species is anti. The different responses of the C14-C15 stretch mode to the Schiff base nitrogen deuteration in bovine and octopus pigments are due to the fact that the coupled C14-C15 stretch and the C12-C13 stretch motions in the model compound or in bovine rhodopsin are altered in octopus rhodopsin so that the stretch motion of the C14-15 bond is more localized, similar to the C-C stretch motion in the small Schiff base model compound. In clear contrast with the bovine rhodopsin Raman spectrum, which is very similar to that for the 11-cis-retinal Schiff base, the drastically different octopus rhodopsin spectrum indicates large protein perturbations on the C11=C12-C13 moiety, either by steric or by electrostatic interactions. Further studies are required to determine if such spectral differences indicate a difference of the energy conversion mechanism in the primary photochemical event of these two pigments.
Collapse
Affiliation(s)
- L Huang
- Department of Physics, City College of City University of New York, New York 10031, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
17
|
Abstract
The mouse adrenocortical Y-1 cell line expresses a high level of neuropeptide Y1 receptor (NPY-Y1). Moreover the receptor density can be up-regulated by dexamethasone or down-regulated by cAMP. To determine whether such regulation occurs at the level of gene expression, Y1 receptor mRNA was measured using a reverse transcriptase-competitive PCR method. Dexamethasone treatment increased Y1 mRNA in Y-1 cells, whereas the cAMP and ACTH decreased it. We also observed that the amount of Y1 receptor RNA was unaffected by phorbol 12-myristate 13-acetate, a protein kinase C stimulator, but was abolished in a cell line expressing apolipoprotein E (apoE). The results indicated that NPY-Y1 receptor mRNA in Y-1 cells is highly regulated by several intracellular messengers. The role of apoE in such regulation is of particular interest in view of evidence that the isoform of the molecule is highly correlated to the age of onset of Alzheimer's disease. The effect observed in the Y-1 cell line which expresses apoE may implicate a possible role of this protein in the process of neuronal death that occurred in the Alzheimer's disease.
Collapse
MESH Headings
- Adrenal Cortex/cytology
- Adrenal Cortex Neoplasms/genetics
- Adrenocorticotropic Hormone/pharmacology
- Animals
- Apolipoproteins E/biosynthesis
- Apolipoproteins E/pharmacology
- Base Sequence
- Cyclic AMP/pharmacology
- DNA Primers/chemistry
- DNA, Complementary/genetics
- Dexamethasone/pharmacology
- Gene Expression Regulation, Neoplastic/drug effects
- Gene Expression Regulation, Neoplastic/genetics
- Glucocorticoids/pharmacology
- Mice
- Polymerase Chain Reaction
- Protein Kinase C/drug effects
- Protein Kinase C/metabolism
- RNA, Messenger/biosynthesis
- RNA, Messenger/drug effects
- RNA, Messenger/genetics
- Rats
- Receptors, Neuropeptide Y/drug effects
- Receptors, Neuropeptide Y/genetics
- Templates, Genetic
- Tetradecanoylphorbol Acetate/pharmacology
- Tumor Cells, Cultured
Collapse
Affiliation(s)
- G Weng
- Department of Neurology and Neuroscience, Cornell University Medical College, New York, NY 10021, USA.
| | | | | | | |
Collapse
|
18
|
Abstract
Various trophic factors present in muscle extract can promote the survival of cultured motor neurones. However, little is known about the signal transduction pathways used in these cells. The proto-oncogene product p21ras has been shown to play an important role in proliferative and differentiative signalling pathways. We report here that cytoplasmic introduction of its oncogenic form, p21ras(G12V), fully supports the in vitro survival of chick embryonic motor neurones. The proto-oncogenic form of p21ras also showed a dose-dependent survival effect, while a C-terminally truncated counterpart of p21ras(G12V) was ineffective. These results suggest an involvement of p21ras in signal transduction pathways leading to motor neurone survival and may be of relevance for the development of therapeutic strategies for motor neurone disease.
Collapse
Affiliation(s)
- G Weng
- Neurologische Klinik, Ludwig-Maximilians-Universität München, Klinikum Grosshadern, Germany
| | | | | | | | | |
Collapse
|
19
|
Xue Y, Weng G, He J, Xu B. [Preparation of oral berberine bisulfate liposomes]. Zhongguo Zhong Yao Za Zhi 1995; 20:730-1, 762-3. [PMID: 8703335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The co-precipitate has been made from berberine bisulfate and polyvingyl pyrrolidone (PVP) with the ratio of 1 : 5. The liposomes entrapped berberine bisulfate have been prepared with the ration of drug to lipid 1 : 20 and the ratio of cholesterol to soy phosphatide 2 : 7. The percentage of encapsulation is 48.72%. The test in vivo of small intestinal absorption in rats shows that liposomes can increase the absorption by 4-fold odd compared with free ber-berine bisulfate.
Collapse
Affiliation(s)
- Y Xue
- Nanjing Institute of Materia Medica
| | | | | | | |
Collapse
|
20
|
Weng G, Yee F, Michl P, Reis D, Wahlestedt C. Studies on neuropeptide Y receptors in a mouse adrenocortical cell line. Mol Pharmacol 1995; 48:9-14. [PMID: 7623780] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The mouse adrenocortical Y-1 cell line has been found to express high affinity binding sites for neuropeptide Y (NPY). Pharmacological studies have shown that these NPY binding sites are of the Y1 type. Reverse transcription-polymerase chain reaction using primers specific for the rat Y1 receptor revealed that the NPY Y1 receptor mRNA is present in Y-1 cells. The Kd of the receptor for NPY was found to be 1.75 +/- 0.20 nM and the Bmax was 265 +/- 18 fmol/mg. The NPY Y1 receptors in this adrenocortical cell line were shown to be coupled to pertussis toxin-sensitive G proteins. Stimulation of Y1 receptors resulted in the inhibition of forskolin- and adrenocorticotropic hormone (ACTH)-stimulated cAMP synthesis. NPY had no effect on basal steroid release from the Y-1 cells. At an ACTH concentration of 0.1 microM, NPY did not affect ACTH-stimulated steroid release, although NPY did inhibit cAMP production under the same hormonal conditions. cAMP profoundly affected the density of the NPY receptors in Y-1 cells. Treatment of the cells with N6,2'-O-dibutyryl-cAMP or ACTH reduced the Y1 receptor density by > 50%. On the other hand the steroid dexamethasone increased the density of Y1 receptors by 35%. Although additional detailed studies are necessary, these results may have interesting implications for the functions of ACTH, steroids, and NPY in the pituitary-adrenocortical axis.
Collapse
Affiliation(s)
- G Weng
- Department of Neurology and Neuroscience, Cornell University Medical College, New York, New York 10021, USA
| | | | | | | | | |
Collapse
|
21
|
Abstract
Three new triterpenoidal saponins, mussaendosides O [1], P [2], and Q [3] were isolated from whole plants of Mussaenda pubescens. These structures were elucidated on the basis of chemical and spectral methods, such as their 1H-1H COSY, HMQC, HMBC, TOCSY, and NOESY nmr spectra.
Collapse
Affiliation(s)
- W Zhao
- Shanghai Institute of Materia Medica, Academia Sinica, People's Republic of China
| | | | | | | | | | | |
Collapse
|
22
|
Abstract
We have utilized Raman difference spectroscopy to investigate hydrogen bonding interactions of the guanine moiety in guanine nucleotides with the binding site of two G proteins, EF-Tu (elongation factor Tu from Escherichia coli) and the c-Harvey ras protein, p21 (the gene product of the human c-H-ras proto-oncogene). Raman spectra of proteins complexed with GDP (guanosine 5' diphosphate), IDP (inosine 5' diphosphate), 6-thio-GDP, and 6-18O-GDP were measured, and the various difference spectra were determined. These were compared to the difference spectra obtained in solution, revealing vibrational features of the nucleotide that are altered upon binding. Specifically, we observed significant frequency shifts in the vibrational modes associated with the 6-keto and 2-amino positions of the guanine group of GDP and IDP that result from hydrogen bonding interactions between these groups and the two proteins. These shifts are interpreted as being proportional to the local energy of interaction (delta H) between the two groups and protein residues at the nucleotide binding site. Consistent with the tight binding between the nucleotides and the two proteins, the shifts indicate that the enthalpic interactions are stronger between these two polar groups and protein than with water. In general, the spectral shifts provide a rationale for the stronger binding of GDP and IDP with p21 compared to EF-Tu. Despite the structural similarity of the binding sites of EF-Tu and p21, the strengths of the observed hydrogen bonds at the 6-keto and 2-amino positions vary substantially, by up to a factor of 2.(ABSTRACT TRUNCATED AT 250 WORDS)
Collapse
Affiliation(s)
- G Weng
- Department of Physics, City College of the City University of New York, New York 10031
| | | | | | | | | |
Collapse
|
23
|
Jazin EE, Yoo H, Blomqvist AG, Yee F, Weng G, Walker MW, Salon J, Larhammar D, Wahlestedt C. A proposed bovine neuropeptide Y (NPY) receptor cDNA clone, or its human homologue, confers neither NPY binding sites nor NPY responsiveness on transfected cells. Regul Pept 1993; 47:247-58. [PMID: 8234909 DOI: 10.1016/0167-0115(93)90392-l] [Citation(s) in RCA: 77] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Receptors with seven transmembrane domains (7TM) constitute a large family of structurally and functionally related proteins which respond to various types of ligands. We describe here the cloning and expression of a human 7TM receptor, denoted hFB22 (human Fetal Brain 22), which is the homologue (92% amino acid identity) of a bovine receptor (LCR1) reported by others to bind neuropeptide Y (NPY) with a pharmacological profile of the Y3 receptor subtype. However, upon expression in COS1 (confirmed by Northern analysis), COS7 or CHO-K1 cells, the hFB22 receptor did not confer specific 125I-Bolton-Hunter-NPY, 3H-propionyl-NPY or 125I-peptide YY (PYY) binding sites, in either intact cells or in membrane preparations. Similarly, cells transfected with the corresponding bovine clone (LCR1) did not show specific NPY/PYY binding exceeding that resulting from endogenous binding sites; mock-transfected COS7 cells, used frequently for heterologous expression of receptors, were found to have endogenous specific 125I-NPY binding sites (Bmax = 112 fmol/mg protein; Kd = 0.25 nM). Moreover, the hFB22 transfected cells, when compared to control transfected cells, did not display de novo NPY- or PYY-induced second messenger responses, i.e., (1) inhibition of forskolin-stimulated cAMP accumulation or (2) 45Ca2+ influx. The presence of hFB22 mRNA was detected in several human neuroblastoma cell lines, none of which was found to express Y3-like NPY binding sites. hFB22 displays 39% amino acid sequence identity (in the transmembrane regions) to the human interleukin-8 receptor, and 32-36% amino acid identity to the human receptors of angiotensin II, bradykinin, and n-formylpeptide, but only 23% amino acid identity to the previously described human NPY/PYY receptor of the Y1 receptor subtype. Our results show that hFB22 and LCR1 do not encode NPY receptors, and their true ligand(s) remains to be identified.
Collapse
Affiliation(s)
- E E Jazin
- Department of Medical Genetics, Uppsala University, Sweden
| | | | | | | | | | | | | | | | | |
Collapse
|
24
|
Williamson WA, Aretz HT, Weng G, Shahian DM, Hamilton WM, Pankratov MM, Shapshay SM. In vitro decalcification of aortic valve leaflets with the Er:YSGG laser, Ho:YAG laser, and the Cavitron ultrasound surgical aspirator. Lasers Surg Med 1993; 13:421-8. [PMID: 8366741 DOI: 10.1002/lsm.1900130405] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
This study was designed to compare the efficacy of the erbium:yttrium-scandium-gallium-garnet (Er:YSGG) laser and the holmium:yttrium-aluminum-garnet (Ho:YAG) lasers in debriding calcium from freshly explanted aortic valve leaflets and to compare the Er:YSGG laser with the Cavitron ultrasonic surgical aspirator (CUSA). Aortic valve leaflets were freshly explanted from patients undergoing aortic valve replacement for aortic stenosis. Initially, 4 leaflets each were debrided with the Er:YSGG and the Ho:YAG lasers to attempt removal of calcium deposits while preserving the underlying integrity of the leaflets and minimizing thermal damage. The Er:YSGG laser was more effective in doing so with less thermal and photoacoustic damage when compared with the Ho:YAG laser. Twelve more leaflets each were then debrided with the Er:YSGG laser and the CUSA. The Er:YSGG laser again proved less injurious to the underlying leaflet. The CUSA-treated leaflets demonstrated shattering and disruption of adjacent tissue as well as collagen fiber exposure. These changes were not seen with the Er:YSGG laser. Because of these properties, the Er:YSGG laser merits further evaluation as a tool for aortic valvuloplasty procedures in selected patients with senescent calcific aortic stenosis.
Collapse
Affiliation(s)
- W A Williamson
- Department of Thoracic and Cardiovascular Surgery, Lahey-Clinic Medical Center, Burlington, Massachusetts 01805
| | | | | | | | | | | | | |
Collapse
|
25
|
Deng H, Manor D, Weng G, Rath P, Koutalos Y, Ebrey T, Gebhard R, Lugtenburg J, Tsuda M, Callender RH. A resonance Raman study of octopus bathorhodopsin with deuterium labeled retinal chromophores. Photochem Photobiol 1991; 54:1001-7. [PMID: 1775525 DOI: 10.1111/j.1751-1097.1991.tb02122.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [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: 12/28/2022]
Abstract
The resonance Raman spectrum of octopus bathorhodopsin in the fingerprint region and in the ethylenic-Schiff base region have been obtained at 80 K using the "pump-probe" technique as have its deuterated chromophore analogues at the C7D; C8D; C8,C7D2; C10D; C11D; C11, C12D2; C14D; C15D; C14, C15D2; and N16D positions. While these data are not sufficient to make definitive band assignments, many tentative assignments can be made. Because of the close spectral similarity between the octopus bathorhodopsin spectrum and that of bovine bathorhodopsin, we conclude that the essential configuration of octopus bathorhodopsin's chromophore is all-trans like. The data suggest that the Schiff base, C = N, configuration is trans (anti). The observed conformationally sensitive fingerprint bands show pronounced isotope shifts upon chromophore deuteration. The size of the shifts differ, in certain cases, from those found for bovine bathorhodopsin. Thus, the internal mode composition of the fingerprint bands differs somewhat from bovine bathorhodopsin, suggesting a somewhat different in situ chromophore conformation. An analysis of the NH bend frequency, the Schiff base C = N stretch frequency, and its shift upon Schiff base deuteration suggests that the hydrogen bonding between the protonated Schiff base with its protein binding pocket is weaker in octopus bathorhodopsin than in bovine bathorhodopsin but stronger than that found in bacteriorhodopsin's bR568 pigment.
Collapse
Affiliation(s)
- H Deng
- Department of Physics, City College of City University of New York, New York 10031
| | | | | | | | | | | | | | | | | | | |
Collapse
|
26
|
Yan M, Manor D, Weng G, Chao H, Rothberg L, Jedju TM, Alfano RR, Callender RH. Ultrafast spectroscopy of the visual pigment rhodopsin. Proc Natl Acad Sci U S A 1991; 88:9809-12. [PMID: 1946406 PMCID: PMC52810 DOI: 10.1073/pnas.88.21.9809] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.2] [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: 12/29/2022] Open
Abstract
We report on time-resolved absorption studies of the bovine visual pigment rhodopsin with subpicosecond resolution at room temperature. Our data show that bathorhodopsin, rhodopsin's early photoproduct, is photochemically formed in 3.0 +/- 0.7 ps. The data suggest that bathorhodopsin formation is kinetically preceded by two species along the rhodopsin-to-bathorhodopsin reaction coordinate. The first is identified with the vertically excited Franck-Condon state. This decays with an approximately 200-fs lifetime to an intermediate, which then decays to bathorhodopsin in 3.0 ps. We assign this intermediate to be an excited state transient near 90 degrees along the 11-12 torsional coordinate of rhodopsin's chromophore. Exchange of rhodopsin's exchangeable protons for deuterons does not affect the observed dynamics. These observations are both qualitatively and quantitatively consistent with molecular dynamics calculations, which model the rhodopsin to bathorhodopsin phototransition as a cis-trans isomerization along the 11-12 torsional coordinate of rhodopsin's chromophore.
Collapse
Affiliation(s)
- M Yan
- Institute of Ultrafast Spectroscopy and Lasers, City College of City University, New York, NY 10031
| | | | | | | | | | | | | | | |
Collapse
|
27
|
Deng H, Manor D, Weng G, Rath P, Koutalos Y, Ebrey T, Gebhard R, Lugtenburg J, Tsuda M, Callender RH. Resonance Raman studies of the HOOP modes in octopus bathorhodopsin with deuterium-labeled retinal chromophores. Biochemistry 1991; 30:4495-502. [PMID: 2021639 DOI: 10.1021/bi00232a018] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [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: 12/29/2022]
Abstract
Resonance Raman spectra of the hydrogen out-of-plane (HOOP) vibrational modes in the retinal chromophore of octopus bathorhodopsin with deuterium label(s) along the polyene chain have been obtained. In clear contrast with bovine bathorhodopsin's HOOP modes, there are only two major HOOP bands at 887 and 940 cm-1 for octopus bathorhodopsin. On the basis of their isotopic shifts upon deuterium labeling, we have assigned the band at 887 cm-1 to C10H and C14H HOOP modes, and the band at 940 cm-1 to C11H = C12H Au-like HOOP mode. Except for a 26 cm-1 downward shift, the C11H = C12H Au-like wag appears to be little disturbed in octopus bathorhodopsin from the chromophore in solution since its changes upon deuterium labeling are close to those found in solution model-compound studies. We found also that the C10H and C14H HOOP wags are also similar to those in the model-compound studies. However, we have found that the interaction between the C7H and C8H HOOP internal coordinates of the chromophore in octopus bathorhodopsin is different from that of the chromophore in solution. The intensity of the C11H = C12H and the other HOOP modes suggests that the chromophore of octopus bathorhodopsin is somewhat torsionally distorted from a planar trans geometry. Importantly, a twist about C11 = C12 double bond is inferred. Such a twist breaks the local symmetry, resulting in the observation of the normally Raman-forbidden C11H = C12H Au-like HOOP mode. The twisted nature of the chromophore, semiquantitatively discussed here, likely affects the lambda max of the chromophore and its enthalpy.(ABSTRACT TRUNCATED AT 250 WORDS)
Collapse
Affiliation(s)
- H Deng
- Department of Physics, City College, City University of New York, New York 10031
| | | | | | | | | | | | | | | | | | | |
Collapse
|