1
|
Wang J, Tian X, Yan C, Wu H, Bu Y, Li J, Liu D, Han Y. TCF7L1 Accelerates Smooth Muscle Cell Phenotypic Switching and Aggravates Abdominal Aortic Aneurysms. JACC Basic Transl Sci 2023; 8:155-170. [PMID: 36908661 PMCID: PMC9998605 DOI: 10.1016/j.jacbts.2022.07.012] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 07/21/2022] [Accepted: 07/21/2022] [Indexed: 12/02/2022]
Abstract
Phenotypic switching of vascular smooth muscle cells is a central process in abdominal aortic aneurysm (AAA) pathology. We found that knockdown TCF7L1 (transcription factor 7-like 1), a member of the TCF/LEF (T cell factor/lymphoid enhancer factor) family of transcription factors, inhibits vascular smooth muscle cell differentiation. This study hints at potential interventions to maintain a normal, differentiated smooth muscle cell state, thereby eliminating the pathogenesis of AAA. In addition, our study provides insights into the potential use of TCF7L1 as a biomarker for AAA.
Collapse
Key Words
- AAA, abdominal aortic aneurysm
- AAV, adeno-associated virus
- Ang II, angiotensin II
- CVF, collagen volume fraction
- MMP, matrix metalloproteinase
- PBS, phosphate-buffered saline
- PCR, polymerase chain reaction
- SM22α, smooth muscle protein 22-α
- SMA, smooth muscle actin
- SRF, serum response factor
- TCF7L1
- TCF7L1, transcription factor 7-like 1
- VSMC, vascular smooth muscle cell
- abdominal aortic aneurysms
- cDNA, complementary DNA
- mRNA, messenger RNA
- phenotypic switching
- siRNA, small interfering RNA
- smooth muscle cell
Collapse
Affiliation(s)
- Jing Wang
- Cardiovascular Research Institute and Department of Cardiology, General Hospital of Northern Theater Command, Shenyang, China
| | - Xiaoxiang Tian
- Cardiovascular Research Institute and Department of Cardiology, General Hospital of Northern Theater Command, Shenyang, China
| | - Chenghui Yan
- Cardiovascular Research Institute and Department of Cardiology, General Hospital of Northern Theater Command, Shenyang, China
| | - Hanlin Wu
- Cardiovascular Research Institute and Department of Cardiology, General Hospital of Northern Theater Command, Shenyang, China
| | - Yuxin Bu
- Cardiovascular Research Institute and Department of Cardiology, General Hospital of Northern Theater Command, Shenyang, China
| | - Jia Li
- Cardiovascular Research Institute and Department of Cardiology, General Hospital of Northern Theater Command, Shenyang, China
| | - Dan Liu
- Cardiovascular Research Institute and Department of Cardiology, General Hospital of Northern Theater Command, Shenyang, China
| | - Yaling Han
- Cardiovascular Research Institute and Department of Cardiology, General Hospital of Northern Theater Command, Shenyang, China
| |
Collapse
|
2
|
Li J, Urabe G, Huang Y, Zhang M, Wang B, Marcho L, Shen H, Kent KC, Guo LW. A Role for Polo-Like Kinase 4 in Vascular Fibroblast Cell-Type Transition. JACC Basic Transl Sci 2021; 6:257-283. [PMID: 33778212 PMCID: PMC7987547 DOI: 10.1016/j.jacbts.2020.12.015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 12/21/2020] [Accepted: 12/21/2020] [Indexed: 11/08/2022]
Abstract
PLK4, previously known as a centriole-associated factor, regulates the transcription factor activity of serum response factor. PLK4 inhibition blocks the profibrogenic cell state transition of vascular fibroblasts. PLK4’s activation and gene expression are regulated by PDGF receptor and epigenetic reader BRD4, respectively. Periadventitial administration of a PLK4 inhibitor mitigates vascular fibrosis.
Polo-like kinase 4 (PLK4) is canonically known for its cytoplasmic function in centriole duplication. Here we show a noncanonical PLK4 function of regulating the transcription factor SRF’s nuclear activity and associated myofibroblast-like cell-type transition. In this context, we have further found that PLK4’s phosphorylation and transcription are respectively regulated by PDGF receptor and epigenetic factor BRD4. Furthermore, in vivo experiments suggest PLK4 inhibition as a potential approach to mitigating vascular fibrosis.
Collapse
Key Words
- AA, PDGF-AA
- BET, bromo/extraterminal domain–containing protein
- BRD4
- BRD4, bromodomain protein 4
- CenB, centrinone-B
- EEL, external elastic lamina
- JQ1, a BET family–selective epigenetic modulator drug
- MRTF-A, myocardin-related transcription factor A
- PDGF receptor
- PDGF, platelet-derived growth factor
- PDGFR, PDGF receptor
- PLK, polo-like kinase
- PLK4
- SRF
- SRF, serum response factor
- fibroblast cell-type transition
- αSMA, α-smooth muscle actin
Collapse
Affiliation(s)
- Jing Li
- Department of Surgery, School of Medicine, University of Virginia, Charlottesville, Virginia, USA
| | - Go Urabe
- Department of Surgery, School of Medicine, University of Virginia, Charlottesville, Virginia, USA
| | - Yitao Huang
- Department of Surgery, School of Medicine, University of Virginia, Charlottesville, Virginia, USA
| | - Mengxue Zhang
- Department of Surgery, School of Medicine, University of Virginia, Charlottesville, Virginia, USA.,Cellular and Molecular Pathology Graduate Program, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin, USA
| | - Bowen Wang
- Department of Surgery, School of Medicine, University of Virginia, Charlottesville, Virginia, USA
| | - Lynn Marcho
- Davis Heart and Lung Research Institute, Wexner Medical Center, Ohio State University, Columbus, Ohio, USA
| | - Hongtao Shen
- Department of Surgery, School of Medicine, University of Virginia, Charlottesville, Virginia, USA
| | - K Craig Kent
- Department of Surgery, School of Medicine, University of Virginia, Charlottesville, Virginia, USA
| | - Lian-Wang Guo
- Department of Surgery, School of Medicine, University of Virginia, Charlottesville, Virginia, USA
| |
Collapse
|
3
|
Wang B, Zhang M, Urabe G, Huang Y, Chen G, Wheeler D, Dornbos DJ 3rd, Huttinger A, Nimjee SM, Gong S, Guo LW, Kent KC. PERK Inhibition Mitigates Restenosis and Thrombosis: A Potential Low-Thrombogenic Antirestenotic Paradigm. JACC Basic Transl Sci 2020; 5:245-63. [PMID: 32215348 DOI: 10.1016/j.jacbts.2019.12.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 12/13/2019] [Accepted: 12/13/2019] [Indexed: 12/18/2022]
Abstract
Drug-eluting stents impede neointimal smooth muscle cell hyperplasia but exacerbate endothelial cell dysfunction and thrombogenicity. It has been a challenge to identify a common target to inhibit both. Findings in this study suggest PERK as such a target. A PERK inhibitor administered either via an endovascular (in biomimetic nanocarriers) or perivascular (in hydrogel) route effectively mitigated neointimal hyperplasia in rats. Oral gavage of the PERK inhibitor partially preserved the normal blood flow in a mouse model of induced thrombosis. Dampening PERK activity inhibited STAT3 while activating SRF in smooth muscle cells, and also reduced prothrombogenic tissue factor and growth impairment of endothelial cells.
Developing endothelial-protective, nonthrombogenic antirestenotic treatments has been a challenge. A major hurdle to this has been the identification of a common molecular target in both smooth muscle cells and endothelial cells, inhibition of which blocks dysfunction of both cell types. The authors’ findings suggest that the PERK kinase could be such a target. Importantly, PERK inhibition mitigated both restenosis and thrombosis in preclinical models, implicating a low-thrombogenic antirestenotic paradigm.
Collapse
Key Words
- ATF, activating transcription factor
- Ad, adenovirus
- CHOP, CCAAT-enhancer-binding protein homologous protein
- DES, drug-eluting stents
- DMSO, dimethyl sulfoxide
- EC, endothelial cell
- ER, endoplasmic reticulum
- FBS, fetal bovine serum
- GFP, green fluorescent protein
- HA, hemagglutinin
- I/M, intima to media
- IEL, internal elastic lamina
- IH, intimal hyperplasia
- IRE1, inositol-requiring kinase 1
- MRTF-A, myocardin related transcription factor A
- PDGF, platelet-derived growth factor
- PDGF-BB, platelet-derived growth factor with 2 B subunits
- PERK
- PERK, protein kinase RNA-like endoplasmic reticulum kinase
- SMA, smooth muscle actin
- SMC, smooth muscle cell
- SRF, serum response factor
- STAT3, signal transducer and activator of transcription 3
- TNF, tumor necrosis factor
- eIF2, eukaryotic translation initiation factor 2
- endothelial cells
- restenosis
- siRNA, small interfering ribonucleic acid
- smooth muscle cells
- thrombosis
Collapse
|
4
|
Zhang M, Urabe G, Little C, Wang B, Kent AM, Huang Y, Kent KC, Guo LW. HDAC6 Regulates the MRTF-A/SRF Axis and Vascular Smooth Muscle Cell Plasticity. JACC Basic Transl Sci 2018; 3:782-795. [PMID: 30623138 PMCID: PMC6314972 DOI: 10.1016/j.jacbts.2018.08.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Revised: 07/31/2018] [Accepted: 08/23/2018] [Indexed: 01/04/2023]
Abstract
Distinct from other histone deacetylases, HDAC6 primarily resides in the cytosol. Unexpectedly, HDAC6-selective inhibition (or silencing) enhances the nuclear activity of SRF. HDAC6 inhibition elevates acetylation and protein levels of myocardin-related transcription factor A, a cytoplasmic-nuclear shuttling co-activator of SRF. Myocardin-related transcription factor A/SRF are known to critically regulate vascular smooth muscle cell phenotypic stability. HDAC6 inhibition prevents smooth muscle cell dedifferentiation in vitro and reduces neointima and restenosis in vivo.
Cellular plasticity is fundamental in biology and disease. Vascular smooth muscle cell (SMC) dedifferentiation (loss of contractile proteins) initiates and perpetrates vascular pathologies such as restenosis. Contractile gene expression is governed by the master transcription factor, serum response factor (SRF). Unlike other histone deacetylases, histone deacetylase 6 (HDAC6) primarily resides in the cytosol. Whether HDAC6 regulates SRF nuclear activity was previously unknown in any cell type. This study found that selective inhibition of HDAC6 with tubastatin A preserved the contractile protein (alpha-smooth muscle actin) that was otherwise diminished by platelet-derived growth factor-BB. Tubastatin A also enhanced SRF transcriptional (luciferase) activity, and this effect was confirmed by HDAC6 knockdown. Interestingly, HDAC6 inhibition increased acetylation and total protein of myocardin-related transcription factor A (MRTF-A), a transcription co-activator known to translocate from the cytosol to the nucleus, thereby activating SRF. Consistently, HDAC6 co-immunoprecipitated with MRTF-A. In vivo studies showed that tubastatin A treatment of injured rat carotid arteries mitigated neointimal lesion, which is known to be formed largely by dedifferentiated SMCs. This report is the first to show HDAC6 regulation of the MRTF-A/SRF axis and SMC plasticity, thus opening a new perspective for interventions of vascular pathologies.
Collapse
Key Words
- DMEM, Dulbecco’s modified Eagle’s medium
- DNA, deoxyribonucleic acid
- EEL, external elastic lamina
- FBS, fetal bovine serum
- HDAC, histone deacetylase
- HDAC6
- IEL, internal elastic lamina
- IH, intimal hyperplasia
- IgG, immunoglobulin G
- MMP, matrix metalloproteinase
- MRTF-A
- MRTF-A, myocardin-related transcription factor A
- PDGF-BB, platelet-derived growth factor-BB
- SMA, smooth muscle actin
- SMC, vascular smooth muscle cell
- SMHC, smooth muscle myosin heavy chain
- SRF
- SRF, serum response factor
- TNF, tumor necrosis factor
- TSA, trichostatin A
- dedifferentiation
- siRNA, small interfering ribonucleic acid
- vascular smooth muscle cell
Collapse
Affiliation(s)
- Mengxue Zhang
- Department of Surgery and Department of Physiology and Cell Biology, College of Medicine, and the Davis Heart and Lung Research Institute, Wexner Medical Center, The Ohio State University, Columbus, Ohio.,Cellular and Molecular Pathology Graduate Program, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin
| | - Go Urabe
- Department of Surgery and Department of Physiology and Cell Biology, College of Medicine, and the Davis Heart and Lung Research Institute, Wexner Medical Center, The Ohio State University, Columbus, Ohio.,Department of Surgery, College of Medicine, and the Davis Heart and Lung Research Institute, Wexner Medical Center, The Ohio State University, Columbus, Ohio
| | - Christopher Little
- Department of Surgery, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin
| | - Bowen Wang
- Department of Surgery, College of Medicine, and the Davis Heart and Lung Research Institute, Wexner Medical Center, The Ohio State University, Columbus, Ohio
| | - Alycia M Kent
- Department of Surgery, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin
| | - Yitao Huang
- Department of Surgery and Department of Physiology and Cell Biology, College of Medicine, and the Davis Heart and Lung Research Institute, Wexner Medical Center, The Ohio State University, Columbus, Ohio
| | - K Craig Kent
- Department of Surgery, College of Medicine, and the Davis Heart and Lung Research Institute, Wexner Medical Center, The Ohio State University, Columbus, Ohio
| | - Lian-Wang Guo
- Department of Surgery and Department of Physiology and Cell Biology, College of Medicine, and the Davis Heart and Lung Research Institute, Wexner Medical Center, The Ohio State University, Columbus, Ohio
| |
Collapse
|
5
|
Ahluwalia A, Jones MK, Hoa N, Zhu E, Brzozowski T, Tarnawski AS. Reduced NGF in Gastric Endothelial Cells Is One of the Main Causes of Impaired Angiogenesis in Aging Gastric Mucosa. Cell Mol Gastroenterol Hepatol 2018; 6:199-213. [PMID: 29992182 PMCID: PMC6037903 DOI: 10.1016/j.jcmgh.2018.05.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Accepted: 05/10/2018] [Indexed: 02/06/2023]
Abstract
BACKGROUND & AIMS Aging gastric mucosa has increased susceptibility to injury and delayed healing owing to impaired angiogenesis, but the mechanisms are not fully known. We examined whether impairment of angiogenesis in aging gastric mucosa is caused by deficiency of nerve growth factor (NGF) in gastric endothelial cells (ECs), and whether NGF therapy could reverse this impairment. METHODS In gastric mucosal ECs (GECs) isolated from young and aging rats we examined the following: (1) in vitro angiogenesis, (2) NGF expression, and (3) the effect of NGF treatment on angiogenesis, GEC proliferation and migration, and dependence on serum response factor. In in vivo studies in young and aging rats, we examined NGF expression in gastric mucosa and the effect of NGF treatment on angiogenesis and gastric ulcer healing. To determine human relevance, we examined NGF expression in gastric mucosal biopsy specimens of aging (≥70 y) and young (≤40 y) individuals. RESULTS In cultured aging GECs, NGF expression and angiogenesis were reduced significantly by 3.0-fold and 4.1-fold vs young GECs. NGF therapy reversed impairment of angiogenesis in aging GECs, and serum response factor silencing completely abolished this response. In gastric mucosa of aging rats, NGF expression in GECs was reduced significantly vs young rats. In aging rats, local NGF treatment significantly increased angiogenesis and accelerated gastric ulcer healing. In aging human subjects, NGF expression in ECs of gastric mucosal vessels was 5.5-fold reduced vs young individuals. CONCLUSIONS NGF deficiency in ECs is a key mechanism underlying impaired angiogenesis and delayed ulcer healing in aging gastric mucosa. Local NGF therapy can reverse these impairments.
Collapse
Key Words
- Aging
- Akt, serine threonine kinase signaling protein
- Angiogenesis
- BrdU, bromodeoxyuridine
- EC, endothelial cell
- Endothelial Cells
- FITC, fluorescein isothiocyanate
- GEC, gastric mucosal microvascular endothelial cells isolated from rats
- GU, gastric ulcer
- Gene Therapy
- LV-GFP, lentiviral green fluorescent protein
- LV-NGF, lentiviral nerve growth factor
- NGF, nerve growth factor
- NSAID, nonsteroidal anti-inflammatory drug
- Nerve Growth Factor
- PBS, phosphate-buffered saline
- PCNA, proliferating cell nuclear antigen
- PCR, polymerase chain reaction
- PI3, phosphoinositide-3
- SRF, serum response factor
- Ulcer Healing
- VEGF, vascular endothelial growth factor
- mRNA, messenger RNA
- mTOR, mammalian target of rapamycin
- siRNA, small interfering RNA
Collapse
Affiliation(s)
- Amrita Ahluwalia
- Medical and Research Services, Veterans Affairs Long Beach Healthcare System, Long Beach, California
| | - Michael K. Jones
- Medical and Research Services, Veterans Affairs Long Beach Healthcare System, Long Beach, California
- Department of Medicine, University of California, Irvine, California
| | - Neil Hoa
- Medical and Research Services, Veterans Affairs Long Beach Healthcare System, Long Beach, California
| | - Ercheng Zhu
- Medical and Research Services, Veterans Affairs Long Beach Healthcare System, Long Beach, California
| | - Tomasz Brzozowski
- Department of Physiology, Jagiellonian University Medical College, Krakow, Poland
| | - Andrzej S. Tarnawski
- Medical and Research Services, Veterans Affairs Long Beach Healthcare System, Long Beach, California
- Department of Medicine, University of California, Irvine, California
- Correspondence Address correspondence to: Andrzej S. Tarnawski, MD, PhD, AGAF, FACG, Veterans Affairs Long Beach Healthcare System, 5901 East 7th Street, 09/151, Long Beach, California 90822. fax: (562) 826-5675.
| |
Collapse
|
6
|
Abstract
Extracellular matrix proteins of the tenascin family resemble each other in their domain structure, and also share functions in modulating cell adhesion and cellular responses to growth factors. Despite these common features, the 4 vertebrate tenascins exhibit vastly different expression patterns. Tenascin-R is specific to the central nervous system. Tenascin-C is an “oncofetal” protein controlled by many stimuli (growth factors, cytokines, mechanical stress), but with restricted occurrence in space and time. In contrast, tenascin-X is a constituitive component of connective tissues, and its level is barely affected by external factors. Finally, the expression of tenascin-W is similar to that of tenascin-C but even more limited. In accordance with their highly regulated expression, the promoters of the tenascin-C and -W genes contain TATA boxes, whereas those of the other 2 tenascins do not. This article summarizes what is currently known about the complex transcriptional regulation of the 4 tenascin genes in development and disease.
Collapse
Key Words
- AKT, v-akt murine thymoma viral oncogene homolog
- ALK, anaplastic lymphoma kinase
- AP-1, activator protein-1
- ATF, activating transcription factor
- BMP, bone morphogenetic protein
- CBP, CREB binding protein
- CREB, cAMP response element-binding protein
- CREB-RP, CREB-related protein
- CYP21A2, cytochrome P450 family 21 subfamily A polypeptide 2
- ChIP, chromatin immunoprecipitation
- EBS, Ets binding site
- ECM, extracellular matrix
- EGF, epidermal growth factor
- ERK1/2, extracellular signal-regulated kinase 1/2
- ETS, E26 transformation-specific
- EWS-ETS, Ewing sarcoma-Ets fusion protein
- Evx1, even skipped homeobox 1
- FGF, fibroblast growth factor
- HBS, homeodomain binding sequence
- IL, interleukin
- ILK, integrin-linked kinase
- JAK, Janus kinase
- JNK, c-Jun N-terminal kinase
- MHCIII, major histocompatibility complex class III
- MKL1, megakaryoblastic leukemia-1
- NFκB, nuclear factor kappa B
- NGF, nerve growth factor; NFAT, nuclear factor of activated T-cells
- OTX2, orthodenticle homolog 2
- PDGF, platelet-derived growth factor
- PI3K, phosphatidylinositol 3-kinase
- POU3F2, POU domain class 3 transcription factor 2
- PRRX1, paired-related homeobox 1
- RBPJk, recombining binding protein suppressor of hairless
- ROCK, Rho-associated, coiled-coil-containing protein kinase
- RhoA, ras homolog gene family member A
- SAP, SAF-A/B, Acinus, and PIAS
- SCX, scleraxix
- SEAP, secreted alkaline phosphatase
- SMAD, small body size - mothers against decapentaplegic
- SOX4, sex determining region Y-box 4
- SRE, serum response element
- SRF, serum response factor
- STAT, signal transducer and activator of transcription
- TGF-β, transforming growth factor-β
- TNC, tenascin-C
- TNF-α, tumor necrosis factor-α
- TNR, tenascin-R
- TNW, tenascin-W
- TNX, tenascin-X
- TSS, transcription start site
- UTR, untranslated region
- WNT, wingless-related integration site
- cancer
- cytokine
- development
- extracellular matrix
- gene promoter
- gene regulation
- glucocorticoid
- growth factor
- homeobox gene
- matricellular
- mechanical stress
- miR, micro RNA
- p38 MAPK, p38 mitogen activated protein kinase
- tenascin
- transcription factor
Collapse
Affiliation(s)
- Francesca Chiovaro
- a Friedrich Miescher Institute for Biomedical Research ; Basel , Switzerland
| | | | | |
Collapse
|
7
|
Chiba S, Enami T, Ogawa S, Sakata-Yanagimoto M. G17V RHOA: Genetic evidence of GTP-unbound RHOA playing a role in tumorigenesis in T cells. Small GTPases 2015; 6:100-3. [PMID: 26103434 DOI: 10.4161/21541248.2014.988088] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
RHOA is a member of RHO family small GTPases. Over the past 2 decades, numerous biochemical and cell biological studies on RHOA have demonstrated signalings such as activation of RHO-associated coiled-coil forming kinases through guanine nucleotide exchange and GTP hydrolysis, cellular responses such as actin fiber formation and myocin activation, biological consequences such as cell motility and cytokineses, etc. There have also been a plenty of active discussion on the roles of RHOA in tumorigenesis, primarily based on gain- and loss-of-function experiments. However, cell-type-specific functions of RHOA have only recently been delineated by conditional gene targeting strategies. Furthermore, very little information had been available on human cancer genetics until we and others recently reported frequent somatic RHOA mutations in a distinct subtype of T-cell-type malignant lymphoma called angioimmunoblastic T-cell lymphoma (AITL), and other T-cell lymphoma with AITL-like features. The RHOA mutations were very specific to these types of lymphoma among hematologic malignancies, and a single hotspot, glycine at the 17th position, was affected by the replacement with valine (G17V). Remarkably, G17V RHOA did not bind GTP, and moreover, it inhibited the GTP binding to wild-type RHOA. How G17V RHOA contributes to T-cell lymphomagenesis needs to be clarified.
Collapse
Affiliation(s)
- Shigeru Chiba
- a Department of Hematology; Faculty of Medicine; University of Tsukuba ; Tskuba , Japan
| | | | | | | |
Collapse
|
8
|
Ishikawa M, Shiota J, Ishibashi Y, Hakamata T, Shoji S, Fukuchi M, Tsuda M, Shirao T, Sekino Y, Ohtsuka T, Baraban JM, Tabuchi A. Identification, expression and characterization of rat isoforms of the serum response factor (SRF) coactivator MKL1. FEBS Open Bio 2013; 3:387-93. [PMID: 24251100 PMCID: PMC3821035 DOI: 10.1016/j.fob.2013.09.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [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: 06/05/2013] [Revised: 08/21/2013] [Accepted: 09/04/2013] [Indexed: 11/25/2022] Open
Abstract
Megakaryoblastic leukemia 1 (MKL1) is a member of the MKL family of serum response factor (SRF) coactivators. Here we have identified three rat MKL1 transcripts: two are homologues of mouse MKL1 transcripts, full-length MKL1 (FLMKL1) and basic, SAP, and coiled-coil domains (BSAC), the third is a novel transcript, MKL1-elongated derivative of yield (MELODY). These rat MKL1 transcripts are differentially expressed in a wide variety of tissues with highest levels in testis and brain. During brain development, these transcripts display differential patterns of expression. The FLMKL1 transcript encodes two isoforms that utilize distinct translation start sites. The longer form possesses three actin-binding RPXXXEL (RPEL) motifs and the shorter form, MKL1met only has two RPEL motifs. All four rat MKL1 isoforms, FLMKL1, BSAC, MKL1met and MELODY increased SRF-mediated transcription, but not CREB-mediated transcription. Accordingly, the differential expression of MKL1 isoforms may help fine-tune gene expression during brain development. Megakaryoblastic leukemia 1 (MKL1) is a serum response factor (SRF) coactivator. We have identified multiple rat MKL1 isoforms, including a novel one named MELODY. Rat MKL1 isoforms are enriched in testis and brain. Expression of rat MKL1 isoforms is regulated during brain development. All rat MKL1 isoforms act as SRF transcriptional coactivators.
Collapse
Key Words
- Alternative promoter
- BSAC, basic, SAP, and coiled-coil domains
- DAPI, 4′, 6-diamidino-2-phenylindole
- GFP, green fluorescent protein
- MAL, megakaryocytic acute leukemia
- MELODY, MKL1-elongated derivative of yield
- MKL1, megakaryoblastic leukemia 1
- Megakaryoblastic leukemia
- RPEL, arginine proline XXX glutamate leucine
- SRF, serum response factor
- Serum response factor
- Transcript
- Transcriptional coactivator
Collapse
Affiliation(s)
- Mitsuru Ishikawa
- Laboratory of Molecular Neurobiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|