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Li P, Chen Y, Mak KK, Wong CK, Wang CC, Yuan P. Functional role of Mst1/Mst2 in embryonic stem cell differentiation. PLoS One 2013; 8:e79867. [PMID: 24224013 PMCID: PMC3818222 DOI: 10.1371/journal.pone.0079867] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2013] [Accepted: 09/26/2013] [Indexed: 02/07/2023] Open
Abstract
The Hippo pathway is an evolutionary conserved pathway that involves cell proliferation, differentiation, apoptosis and organ size regulation. Mst1 and Mst2 are central components of this pathway that are essential for embryonic development, though their role in controlling embryonic stem cells (ES cells) has yet to be exploited. To further understand the Mst1/Mst2 function in ES cell pluripotency and differentiation, we derived Mst1/Mst2 double knockout (Mst-/-) ES cells to completely perturb Hippo signaling. We found that Mst-/- ES cells express higher level of Nanog than wild type ES cells and show differentiation resistance after LIF withdrawal. They also proliferate faster than wild type ES cells. Although Mst-/- ES cells can form embryoid bodies (EBs), their differentiation into tissues of three germ layers is distorted. Intriguingly, Mst-/- ES cells are unable to form teratoma. Mst-/- ES cells can differentiate into mesoderm lineage, but further differentiation to cardiac lineage cells is significantly affected. Microarray analysis revealed that ligands of non-canonical Wnt signaling, which is critical for cardiac progenitor specification, are significantly repressed in Mst-/- EBs. Taken together our results showed that Mst1/Mst2 are required for proper cardiac lineage cell development and teratoma formation.
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Affiliation(s)
- Peng Li
- Department of Chemical Pathology, the Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, Hong Kong SAR, China
| | - Ying Chen
- Li Ka Shing Institute of Health Sciences, the Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, Hong Kong SAR, China
| | - Kinglun Kingston Mak
- School of Biomedical Sciences, the Chinese University of Hong Kong, Shatin, New Territories, Hong Kong SAR, China
- CUHK Shenzhen Research Institute, the Chinese University of Hong Kong, Shenzhen, Guangdong, China
- Key Laboratories for Regenerative Medicine, Ministry of Education, the Chinese University of Hong Kong, Shatin, New Territories, Hong Kong SAR, China
| | - Chun Kwok Wong
- Department of Chemical Pathology, the Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, Hong Kong SAR, China
- CUHK Shenzhen Research Institute, the Chinese University of Hong Kong, Shenzhen, Guangdong, China
| | - Chi Chiu Wang
- Li Ka Shing Institute of Health Sciences, the Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, Hong Kong SAR, China
- School of Biomedical Sciences, the Chinese University of Hong Kong, Shatin, New Territories, Hong Kong SAR, China
- CUHK Shenzhen Research Institute, the Chinese University of Hong Kong, Shenzhen, Guangdong, China
- Fetal Medicine Unit, Department of Obstetrics and Gynaecology, the Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, Hong Kong SAR, China
| | - Ping Yuan
- Department of Chemical Pathology, the Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, Hong Kong SAR, China
- Li Ka Shing Institute of Health Sciences, the Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, Hong Kong SAR, China
- School of Biomedical Sciences, the Chinese University of Hong Kong, Shatin, New Territories, Hong Kong SAR, China
- CUHK Shenzhen Research Institute, the Chinese University of Hong Kong, Shenzhen, Guangdong, China
- * E-mail:
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102
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Montenegro MF, Sáez-Ayala M, Piñero-Madrona A, Cabezas-Herrera J, Rodríguez-López JN. Reactivation of the tumour suppressor RASSF1A in breast cancer by simultaneous targeting of DNA and E2F1 methylation. PLoS One 2012; 7:e52231. [PMID: 23251702 PMCID: PMC3522638 DOI: 10.1371/journal.pone.0052231] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2012] [Accepted: 11/13/2012] [Indexed: 11/19/2022] Open
Abstract
Background Tumour suppressor genes are often transcriptionally silenced by promoter hypermethylation, and recent research has implicated alterations in chromatin structure as the mechanistic basis for this repression. In addition to DNA methylation, other epigenetic post-translational modifications that modulate the stability and binding of specific transcription factors to gene promoters have emerged as important mechanisms for controlling gene expression. The aim of this study was to analyse the implications of these mechanisms and their molecular connections in the reactivation of RASSF1A in breast cancer. Methods Compounds that modulate the intracellular concentration of adenosine, such as dipyridamole (DIPY), greatly increase the antiproliferative effects of 3-O-(3,4,5-trimethoxybenzoyl)-(−)-catechin (TMCG), a synthetic antifolate derived from the structure of tea catechins. Quantitative real-time PCR arrays and MALDI-TOF mass spectrometry indicated that this combination (TMCG/DIPY) induced apoptosis in breast cancer cells by modulating the methylation levels of DNA and proteins (such as E2F1), respectively. Chromatin immunoprecipitation (ChIP) assays were employed to confirm that this combination induced chromatin remodelling of the RASSF1A promoter and increased the occupancy of E2F1 at the promoter of this tumour suppressor gene. Results The TMCG/DIPY combination acted as an epigenetic treatment that reactivated RASSF1A expression and induced apoptosis in breast cancer cells. In addition to modulating DNA methylation and chromatin remodelling, this combination also induced demethylation of the E2F1 transcription factor. The ChIP assay showed enhancement of E2F1 occupancy at the unmethylated RASSF1A promoter after TMCG/DIPY treatment. Interestingly, inhibition of E2F1 demethylation using an irreversible inhibitor of lysine-specific demethylase 1 reduced both TMCG/DIPY-mediated RASSF1A expression and apoptosis in MDA-MB-231 cells, suggesting that DNA and protein demethylation may act together to control these molecular and cellular processes. Conclusions/Significance This study demonstrates that simultaneous targeting of DNA and E2F1 methylation is an effective epigenetic treatment that reactivates RASSF1A expression and induces apoptosis in breast cancer cells.
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Affiliation(s)
- María F. Montenegro
- Department of Biochemistry and Molecular Biology A, School of Biology, Regional Campus of International Excellence “Campus Mare Nostrum”, University of Murcia, Espinardo, Murcia, Spain
| | - Magali Sáez-Ayala
- Department of Biochemistry and Molecular Biology A, School of Biology, Regional Campus of International Excellence “Campus Mare Nostrum”, University of Murcia, Espinardo, Murcia, Spain
| | - Antonio Piñero-Madrona
- Department of Surgery, University Hospital Virgen de la Arrixaca, Instituto Murciano de Investigación Biomédica, Murcia, Spain
| | - Juan Cabezas-Herrera
- Translational Cancer Research Group, University Hospital Virgen de la Arrixaca, Instituto Murciano de Investigación Biomédica, Murcia, Spain
| | - José Neptuno Rodríguez-López
- Department of Biochemistry and Molecular Biology A, School of Biology, Regional Campus of International Excellence “Campus Mare Nostrum”, University of Murcia, Espinardo, Murcia, Spain
- * E-mail:
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103
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Yabuta N, Mukai S, Okamoto A, Okuzaki D, Suzuki H, Torigata K, Yoshida K, Okada N, Miura D, Ito A, Ikawa M, Okabe M, Nojima H. N-terminal truncation of Lats1 causes abnormal cell growth control and chromosomal instability. J Cell Sci 2012; 126:508-20. [PMID: 23230145 DOI: 10.1242/jcs.113431] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The tumor suppressors Lats1 and Lats2 are mediators of the Hippo pathway that regulates tissue growth and proliferation. Their N-terminal non-kinase regions are distinct except for Lats conserved domains 1 and 2 (LCD1 and LCD2), which may be important for Lats1/2-specific functions. Lats1 knockout mice were generated by disrupting the N-terminal region containing LCD1 (Lats1(ΔN/ΔN)). Some Lats1(ΔN/ΔN) mice were born safely and grew normally. However, mouse embryonic fibroblasts (MEFs) from Lats1(ΔN/ΔN) mice displayed mitotic defects, centrosomal overduplication, chromosomal misalignment, multipolar spindle formation, chromosomal bridging and cytokinesis failure. They also showed anchorage-independent growth and continued cell cycles and cell growth, bypassing cell-cell contact inhibition similar to tumor cells. Lats1(ΔN/ΔN) MEFs produced tumors in nude mice after subcutaneous injection, although the tumor growth rate was much slower than that of ordinary cancer cells. Yap, a key transcriptional coactivator of the Hippo pathway, was overexpressed and stably retained in Lats1(ΔN/ΔN) MEFs in a cell density independent manner, and Lats2 mRNA expression was downregulated. In conclusion, N-terminally truncated Lats1 induced Lats2 downregulation and Yap protein accumulation, leading to chromosomal instability and tumorigenesis.
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Affiliation(s)
- Norikazu Yabuta
- Department of Molecular Genetics, Osaka University, 3-1 Yamadaoka, Suita City, Osaka 565-0871, Japan
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Abstract
This review is focusing on a critical mediator of embryonic and postnatal development with multiple implications in inflammation, neoplasia, and other pathological situations in brain and peripheral tissues. These morphogenetic guidance and dependence processes are involved in several malignancies targeting the epithelial and immune systems including the progression of human colorectal cancers. We consider the most important findings and their impact on basic, translational, and clinical cancer research. Expected information can bring new cues for innovative, efficient, and safe strategies of personalized medicine based on molecular markers, protagonists, signaling networks, and effectors inherent to the Netrin axis in pathophysiological states.
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105
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Shull AY, Latham-Schwark A, Ramasamy P, Leskoske K, Oroian D, Birtwistle MR, Buckhaults PJ. Novel somatic mutations to PI3K pathway genes in metastatic melanoma. PLoS One 2012; 7:e43369. [PMID: 22912864 PMCID: PMC3422312 DOI: 10.1371/journal.pone.0043369] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2012] [Accepted: 07/23/2012] [Indexed: 01/13/2023] Open
Abstract
Background BRAFV600 inhibitors have offered a new gateway for better treatment of metastatic melanoma. However, the overall efficacy of BRAFV600 inhibitors has been lower than expected in clinical trials, and many patients have shown resistance to the drug’s effect. We hypothesized that somatic mutations in the Phosphoinositide 3-Kinase (PI3K) pathway, which promotes proliferation and survival, may coincide with BRAFV600 mutations and contribute to chemotherapeutic resistance. Methods We performed a somatic mutation profiling study using the 454 FLX pyrosequencing platform in order to identify candidate cancer genes within the MAPK and PI3K pathways of melanoma patients. Somatic mutations of theses candidate cancer genes were then confirmed using Sanger sequencing. Results As expected, BRAFV600 mutations were seen in 51% of the melanomas, whereas NRAS mutations were seen in 19% of the melanomas. However, PI3K pathway mutations, though more heterogeneous, were present in 41% of the melanoma, with PTEN being the highest mutated PI3K gene in melanomas (22%). Interestingly, several novel PI3K pathway mutations were discovered in MTOR, IRS4, PIK3R1, PIK3R4, PIK3R5, and NFKB1. PI3K pathway mutations co-occurred with BRAFV600 mutations in 17% of the tumors and co-occurred with 9% of NRAS mutant tumors, implying cooperativity between these pathways in terms of melanoma progression. Conclusions These novel PI3K pathway somatic mutations could provide alternative survival and proliferative pathways for metastatic melanoma cells. They therefore may be potential chemotherapeutic targets for melanoma patients who exhibit resistance to BRAFV600 inhibitors.
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Affiliation(s)
- Austin Y. Shull
- Georgia Health Sciences University Cancer Center, Georgia Health Sciences University, Augusta, Georgia, United States of America
| | - Alicia Latham-Schwark
- Georgia Health Sciences University Cancer Center, Georgia Health Sciences University, Augusta, Georgia, United States of America
- College of Medicine, Medical University of South Carolina, Charleston, South Carolina, United States of America
| | - Poornema Ramasamy
- Georgia Health Sciences University Cancer Center, Georgia Health Sciences University, Augusta, Georgia, United States of America
| | - Kristin Leskoske
- Georgia Health Sciences University Cancer Center, Georgia Health Sciences University, Augusta, Georgia, United States of America
- Department of Molecular and Cell Biology, University of California, Berkeley, California, United States of America
| | - Dora Oroian
- Georgia Health Sciences University Cancer Center, Georgia Health Sciences University, Augusta, Georgia, United States of America
| | - Marc R. Birtwistle
- Georgia Health Sciences University Cancer Center, Georgia Health Sciences University, Augusta, Georgia, United States of America
| | - Phillip J. Buckhaults
- Georgia Health Sciences University Cancer Center, Georgia Health Sciences University, Augusta, Georgia, United States of America
- * E-mail:
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106
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Protein kinases of the Hippo pathway: regulation and substrates. Semin Cell Dev Biol 2012; 23:770-84. [PMID: 22898666 DOI: 10.1016/j.semcdb.2012.07.002] [Citation(s) in RCA: 185] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2012] [Accepted: 07/31/2012] [Indexed: 01/30/2023]
Abstract
The "Hippo" signaling pathway has emerged as a major regulator of cell proliferation and survival in metazoans. The pathway, as delineated by genetic and biochemical studies in Drosophila, consists of a kinase cascade regulated by cell-cell contact and cell polarity that inhibits the transcriptional coactivator Yorkie and its proliferative, anti-differentiation, antiapoptotic transcriptional program. The core pathway components are the GC kinase Hippo, which phosphorylates the noncatalytic polypeptide Mats/Mob1 and, with the assistance of the scaffold protein Salvador, phosphorylates the ndr-family kinase Lats. In turn phospho-Lats, after binding to phospho-Mats, autoactivates and phosphorylates Yorkie, resulting in its nuclear exit. Hippo also uses the scaffold protein Furry and a different Mob protein to control another ndr-like kinase, the morphogenetic regulator Tricornered. Architecturally homologous kinase cascades consisting of a GC kinase, a Mob protein, a scaffolding polypeptide and an ndr-like kinase are well described in yeast; in Saccharomyces cerevisiae, e.g., the MEN pathway promotes mitotic exit whereas the RAM network, using a different GC kinase, Mob protein, scaffold and ndr-like kinase, regulates cell polarity and morphogenesis. In mammals, the Hippo orthologs Mst1 and Mst2 utilize the Salvador ortholog WW45/Sav1 and other scaffolds to regulate the kinases Lats1/Lats2 and ndr1/ndr2. As in Drosophila, murine Mst1/Mst2, in a redundant manner, negatively regulate the Yorkie ortholog YAP in the epithelial cells of the liver and gut; loss of both Mst1 and Mst2 results in hyperproliferation and tumorigenesis that can be largely negated by reduction or elimination of YAP. Despite this conservation, considerable diversification in pathway composition and regulation is already evident; in skin, e.g., YAP phosphorylation is independent of Mst1Mst2 and Lats1Lats2. Moreover, in lymphoid cells, Mst1/Mst2, under the control of the Rap1 GTPase and independent of YAP, promotes integrin clustering, actin remodeling and motility while restraining the proliferation of naïve T cells. This review will summarize current knowledge of the structure and regulation of the kinases Hippo/Mst1&2, their noncatalytic binding partners, Salvador and the Rassf polypeptides, and their major substrates Warts/Lats1&2, Trc/ndr1&2, Mats/Mob1 and FOXO.
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107
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Ulivi P, Capelli L, Valgiusti M, Zoli W, Scarpi E, Chiadini E, Rosetti P, Bravaccini S, Calistri D, Saragoni L, Casadei Gardini A, Ragazzini A, Frassineti GL, Amadori D, Passardi A. Predictive role of multiple gene alterations in response to cetuximab in metastatic colorectal cancer: a single center study. J Transl Med 2012; 10:87. [PMID: 22569004 PMCID: PMC3404915 DOI: 10.1186/1479-5876-10-87] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2012] [Accepted: 05/08/2012] [Indexed: 12/26/2022] Open
Abstract
Background KRAS mutations negatively affect outcome after treatment with cetuximab in metastatic colorectal cancer (mCRC) patients. As only 20% of KRAS wild type (WT) patients respond to cetuximab it is possible that other mutations, constitutively activating the EGFR pathway, are present in the non-responding KRAS WT patients. We retrospectively analyzed objective tumor response rate, (ORR) progression-free (PFS) and overall survival (OS) with respect to the mutational status of KRAS, BRAF, PIK3CA and PTEN expression in mCRC patients treated with a cetuximab-based regimen. Methods 67 mCRC patients were enrolled onto the study. DNA was extracted from paraffin-embedded sections derived from primary or metastatic lesions. Exon 2 of KRAS and exon 15 of BRAF were analyzed by direct sequencing, PIK3CA was evaluated by pyrosequencing and PTEN expression by immunohistochemistry. Results BRAF and PIK3CA mutations were independently associated with worse PFS (p = 0.006 and p = 0.028, respectively) and OS (p = 0.008 and p = 0.029, respectively). No differences in clinical outcome were found between patients who were positive or negative for PTEN expression. Conversely, patients negative for KRAS, BRAF and PIK3CA mutations were characterized by significantly better ORR, PFS and OS than patients with at least one of these mutations. Conclusions BRAF and PIK3CA mutations would seem to be independent predictors of anti-EGFR therapy effectiveness and could be taken into consideration during treatment decision making.
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Affiliation(s)
- Paola Ulivi
- Biosciences Laboratory, IRCCS Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (I.R.S.T.), Via Maroncelli 40, 47014 Meldola (FC), Italy
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Hergovich A, Hemmings BA. Hippo signalling in the G2/M cell cycle phase: lessons learned from the yeast MEN and SIN pathways. Semin Cell Dev Biol 2012; 23:794-802. [PMID: 22525225 DOI: 10.1016/j.semcdb.2012.04.001] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2012] [Revised: 04/03/2012] [Accepted: 04/04/2012] [Indexed: 01/11/2023]
Abstract
Over the past decade Hippo kinase signalling has been established as an essential tumour suppressor pathway controlling tissue growth in flies and mammals. All members of the Hippo core signalling cassette are conserved from yeast to humans, whereby the yeast analogues of Hippo, Mats and Lats are central components of the mitotic exit network and septation initiation network in budding and fission yeast, respectively. Here, we discuss how far core Hippo signalling components in Drosophila melanogaster and mammals have reported similar mitotic functions as already established for their highly conserved yeast counterparts.
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RASSF Signalling and DNA Damage: Monitoring the Integrity of the Genome? Mol Biol Int 2012; 2012:141732. [PMID: 22577550 PMCID: PMC3337673 DOI: 10.1155/2012/141732] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2011] [Accepted: 01/27/2012] [Indexed: 12/14/2022] Open
Abstract
The RASSF family of proteins has been extensively studied in terms of their genetics, structure and function. One of the functions that has been increasingly studied is the role of the RASSF proteins in the DNA damage response. Surprisingly, this research, which encompasses both the classical and N-terminal RASSF proteins, has revealed an involvement of the RASSFs in oncogenic pathways as well as the more familiar tumour suppressor pathways usually associated with the RASSF family members. The most studied protein with respect to DNA damage is RASSF1A, which has been shown, not only to be activated by ATM, a major regulator of the DNA damage response, but also to bind to and activate a number of different pathways which all lead to and feedback from the guardian of the genome, p53. In this review we discuss the latest research linking the RASSF proteins to DNA damage signalling and maintenance of genomic integrity and look at how this knowledge is being utilised in the clinic to enhance the effectiveness of traditional cancer therapies such as radiotherapy.
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110
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RASSF1A Signaling in the Heart: Novel Functions beyond Tumor Suppression. Mol Biol Int 2012; 2012:154283. [PMID: 22577551 PMCID: PMC3337625 DOI: 10.1155/2012/154283] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2012] [Accepted: 03/26/2012] [Indexed: 01/07/2023] Open
Abstract
The RASSF proteins are a family of polypeptides, each containing a conserved Ras association domain, suggesting that these scaffold proteins may be effectors of activated Ras or Ras-related small GTPases. RASSF proteins are characterized by their ability to inhibit cell growth and proliferation while promoting cell death. RASSF1 isoform A is an established tumor suppressor and is frequently silenced in a variety of tumors and human cancer cell lines. However, our understanding of its function in terminally differentiated cell types, such as cardiac myocytes, is relatively nascent. Herein, we review the role of RASSF1A in cardiac physiology and disease and highlight signaling pathways that mediate its function.
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