Lamin A/C modulates spatial organization and function of the Hsp70 gene locus via nuclear myosin I

Approximately 116 unique mutations in the lamin A/C gene have been described to date that are associated with dilated cardiomyopathy. We recently reported the discovery of MLIP through its interaction with lamin A/C. MLIP is expressed ubiquitously and most abundantly in heart, skeletal and smooth muscle of amniotes (mammals, reptiles and birds) and has no paralogous homologue suggesting no functional redundancy. The MLIP gene encodes at least seven, alternatively spliced, LMNA-interacting factors that possess several structural motifs not found in any other protein. The MLIP isoforms pattern of expression differs between each of the tissues with heart being the most heterogeneous. Down-regulation of lamin A/C expression by shRNA results in the up-regulation and mis-localization of MLIP. In addition to interacting and co-localizing with lamin A/C we also demonstrated that MLIP localizes to micro-domains in the nucleus with promyelocytic leukemia protein (PML) in close proximity to chromatin. MLIP's biological function still remains elusive. Eight week old hemizygous MLIP null mice develop enlarged hearts with a significant increase in heart to body weights (MLIP+/+ 5.62mg/g vs MLIP+/- 10.73mg/g, p<0.0001 n=7) with an overall 30% increase in the anterior-posterior ventricle length of MLIP hearts while maintaining a normal body weight (Figure). Echocardiographic analysis of MLIP+/- mice revealed that their hearts as having a significant (p3.93mm with a significant (p=0.011, n=12) reduction of left ventricular fractional shorting (LVFS) 31% when compare to littermate controls. Histological analysis of the hearts showed no overt phenotype other than an overall increase in the size of the MLIP+/- hearts. The cellular source for the increase in heart size and mass remains to be determined if it is the product of an increase in the number of cardiomyocytes due to aberrant hyperplasia or an increase in cardiomyocyte size through cellular hypertrophy. In conclusion, MLIP is a newly discovered lamin interacting protein that may serve as a transcriptional regulator that impact genes involved in heart development, growth and function and provides a new signaling paradigm.

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TEDs Site Phosphorylation Regulates Myosin I Motor Activity And Function In Fission Yeast

Biophysical Journal ◽

10.1016/j.bpj.2008.12.2954 ◽

2009 ◽

Vol 96 (3) ◽

pp. 545a-546a

Author(s):

Sheran L. Attanapola ◽

Daniel P. Mulvihill

Keyword(s):

Motor Activity ◽

Fission Yeast ◽

Myosin I ◽

And Function

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Concentration-dependent lamin assembly and its roles in the localization of other nuclear proteins

Molecular Biology of the Cell ◽

10.1091/mbc.e13-11-0644 ◽

2014 ◽

Vol 25 (8) ◽

pp. 1287-1297 ◽

Cited By ~ 39

Author(s):

Yuxuan Guo ◽

Youngjo Kim ◽

Takeshi Shimi ◽

Robert D. Goldman ◽

Yixian Zheng

Keyword(s):

Nuclear Lamina ◽

Nuclear Pore ◽

Lamin A ◽

Nuclear Pore Complexes ◽

Developmental Defects ◽

Protein Levels ◽

Lamin B1 ◽

Mouse Cells ◽

Pore Complexes ◽

And Function

The nuclear lamina (NL) consists of lamin polymers and proteins that bind to the polymers. Disruption of NL proteins such as lamin and emerin leads to developmental defects and human diseases. However, the expression of multiple lamins, including lamin-A/C, lamin-B1, and lamin-B2, in mammals has made it difficult to study the assembly and function of the NL. Consequently, it has been unclear whether different lamins depend on one another for proper NL assembly and which NL functions are shared by all lamins or are specific to one lamin. Using mouse cells deleted of all or different combinations of lamins, we demonstrate that the assembly of each lamin into the NL depends primarily on the lamin concentration present in the nucleus. When expressed at sufficiently high levels, each lamin alone can assemble into an evenly organized NL, which is in turn sufficient to ensure the even distribution of the nuclear pore complexes. By contrast, only lamin-A can ensure the localization of emerin within the NL. Thus, when investigating the role of the NL in development and disease, it is critical to determine the protein levels of relevant lamins and the intricate shared or specific lamin functions in the tissue of interest.

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Abstract 15552: Acute Estrogen-GPER1 Stimulation Preserves Mitochondrial Inner Membrane Protein (Mitofilin) From Degradation caused by Ischemia/Reperfusion Stress

Circulation ◽

10.1161/circ.130.suppl_2.15552 ◽

2014 ◽

Vol 130 (suppl_2) ◽

Author(s):

Tanoya L. C Harris ◽

Bjorn Olde ◽

Fredrik Leeb-Lundberg ◽

Jean C. Bopassa

Keyword(s):

Electron Microscopy ◽

Spatial Organization ◽

Ischemia Reperfusion ◽

Estrogen Treatment ◽

Mitochondrial Inner Membrane ◽

Mitochondrial Integrity ◽

Inner Membrane Protein ◽

Estrogen Effect ◽

And Function ◽

High Resolution Microscopy

Introduction: We recently found that acute estrogen treatment delays the mitochondrial permeability transition pore opening and reduces ROS production after ischemia/reperfusion, suggesting that estrogen promotes mitochondrial integrity. As mitochondrial inner membrane protein (mitofilin) has been found to control mitochondrial cristae morphology and function, we investigated whether estrogen effect on mitochondrial integrity after ischemia/reperfusion involved regulation of mitofilin via G-Protein Coupled Estrogen Receptor1 (GPER1) activation. Methods: Isolated hearts from male WT (C57BL/6NCrL), and GPER1-/- mice were perfused using Langendorff technique, with and without estrogen (40 nM). Hearts were subjected to 20 min global ischemia followed by 10 min reperfusion. Mitochondria were isolated, and 2D-DIGE followed by mass spectrometry was performed. Mitofilin expression was confirmed by Western blot analysis in mitochondrial fractions. Mitofilin distribution in cardiomyocytes, and its spatial organization in single mitochondria were visualized using high resolution microscopy. Electron microscopy was used to observe the state of mitochondrial cristae morphology. Results: Analysis revealded 52 unique proteins of interest, in which mitofilin was identified. Immunoblot analysis confirmed an increased in mitofilin level with estrogen treatment as compared to control in WT but not in GPER1-/-. We found, as observed in non-ischemic myocytes, that mitofilin in estrogen-treated cardiomyocytes was distributed in the peri-membrane and T-tubules, while only peri-membrane mitofilin was more visible in control group. High resolution microscopy showed a better spatial organization of mitofilin in single mitochondria with estrogen treatment compared to control, in which mitofilin was almost absent. Electron microscopy revealded that mitochondrial morphology was preserved with estrogen treatment, as cristae were well organized compared to control, in which cristae were disrupted. Conclusion: These data indicate that estrogen up-regulates mitofilin expression during ischemia/reperfusion. Estrogen effect on mitofilin may contribute to improved mitochondrial integrity and function.

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Persistent expression of HNF6 in islet endocrine cells causes disrupted islet architecture and loss of beta cell function

Development ◽

10.1242/dev.127.13.2883 ◽

2000 ◽

Vol 127 (13) ◽

pp. 2883-2895 ◽

Cited By ~ 2

Author(s):

M. Gannon ◽

M.K. Ray ◽

K. Van Zee ◽

F. Rausa ◽

R.H. Costa ◽

...

Keyword(s):

Beta Cell ◽

Beta Cells ◽

Endocrine Cells ◽

Spatial Organization ◽

Glucose Transporter ◽

Cell Function ◽

Regulatory Element ◽

Cell Physiology ◽

Pancreatic Ducts ◽

And Function

We used transgenesis to explore the requirement for downregulation of hepatocyte nuclear factor 6 (HNF6) expression in the assembly, differentiation, and function of pancreatic islets. In vivo, HNF6 expression becomes downregulated in pancreatic endocrine cells at 18. 5 days post coitum (d.p.c.), when definitive islets first begin to organize. We used an islet-specific regulatory element (pdx1(PB)) from pancreatic/duodenal homeobox (pdx1) gene to maintain HNF6 expression in endocrine cells beyond 18.5 d.p.c. Transgenic animals were diabetic. HNF6-overexpressing islets were hyperplastic and remained very close to the pancreatic ducts. Strikingly, alpha, delta, and PP cells were increased in number and abnormally intermingled with islet beta cells. Although several mature beta cell markers were expressed in beta cells of transgenic islets, the glucose transporter GLUT2 was absent or severely reduced. As glucose uptake/metabolism is essential for insulin secretion, decreased GLUT2 may contribute to the etiology of diabetes in pdx1(PB)-HNF6 transgenics. Concordantly, blood insulin was not raised by glucose challenge, suggesting profound beta cell dysfunction. Thus, we have shown that HNF6 downregulation during islet ontogeny is critical to normal pancreas formation and function: continued expression impairs the clustering of endocrine cells and their separation from the ductal epithelium, disrupts the spatial organization of endocrine cell types within the islet, and severely compromises beta cell physiology, leading to overt diabetes.

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Quantitative polymorphism of tandem repeats as a method of epigenetic regulation of the of human cells response to oxidative stress

Nauchno-prakticheskii zhurnal «Medicinskaia genetika» ◽

10.25557/2073-7998.2020.12.68-70 ◽

2020 ◽

pp. 68-70

Author(s):

Н.Н. Вейко ◽

Е.С. Ершова ◽

М.С. Конькова ◽

Е.М. Малиновская ◽

С.В. Костюк

Keyword(s):

Adaptive Response ◽

Spatial Organization ◽

Tandem Repeats ◽

Spatial Configuration ◽

Human Cells ◽

Central Regions ◽

Schizophrenic Patients ◽

Response To Stress ◽

Cell Genome ◽

And Function

Пространственная организация хроматина важна для нормального функционирования клетки. На архитектуру ядра влияют размеры отдельных фрагментов генома, которые коррелируют с числом копий этих фрагментов. Перемещение локусов 1q12 от поверхности ядра в центральные области является ключевой стадией адаптивного ответа клетки на стресс. Мы предположили, что размер локусов 1q12, который коррелирует с содержанием повтора f-SatIII, может влиять на перемещение этих участков хроматина в ядре. Методом FISH на выделенных лимфоцитах показали, что в контроле локусы 1q12 расположены вблизи поверхности ядра, в ядрах лимфоцитов больных шизофренией (БШ) и облученных контрольных клеток локусы 1q12 расположены в центральных районах ядра. Длительное культивирование облученных лимфоцитов сопровождалось гибелью клеток, и снижением содержания f-SatIII в ДНК. Очевидно, что погибали клетки с большим размером 1q12 (много f-SatIII), обогащая популяцию клетками с низким содержанием f-SatIII. В клетках БШ и в облученных клетках мы обнаружили повышение уровня РНК SATIII. Размеры гетерохроматина 1q12 в клетках человека могут влиять на процессы пролиферации и ответа клетки на стресс. Количественный полиморфизм тандемных повторов генома - один из эпигенетических механизмов регуляции ответа клеток на окислительный стресс. The spatial organization of chromatin is important for the normal functioning of the cell. Genome repeat cluster sizes can affect the chromatin spatial configuration and function. The 1q12 heterochromatin loci movement from the periphery to the center of the nucleus is the cells’ universal response to various types of stress. We hypothesized that a large 1q12 domain could affect chromatin movement, thereby inhibiting adaptive response (AR). Using the FISH method, we shown that in the control, 1q12 loci are located near the surface of the nucleus; in the lymphocyte nuclei of schizophrenic patients and irradiated control cells, 1q12 loci are located in the central regions of the nucleus. During prolonged cultivation, the irradiated cells with a large Large f-SatIII amount die and the population is enriched with the cells with low f-SatIII content. In intact SZ patients’ lymphocytes and in irradiated cells we found an increase in SATIII RNA levels. The size of heterochromatin 1q12 loci in human cells can affect to the proliferation and cells’ adaptive response to stress. Quantitative polymorphism of tandem genome repeats is one of the epigenetic mechanisms of genome expression’s regulation.

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Mouse Nuclear Myosin I Knock-Out Shows Interchangeability and Redundancy of Myosin Isoforms in the Cell Nucleus

PLoS ONE ◽

10.1371/journal.pone.0061406 ◽

2013 ◽

Vol 8 (4) ◽

pp. e61406 ◽

Cited By ~ 25

Author(s):

Tomáš Venit ◽

Rastislav Dzijak ◽

Alžběta Kalendová ◽

Michal Kahle ◽

Jana Rohožková ◽

...

Keyword(s):

Cell Nucleus ◽

Myosin Isoforms ◽

Knock Out ◽

Myosin I ◽

Nuclear Myosin I

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Photosynthetic hydrogen production by droplet-based microbial micro-reactors under aerobic conditions

Nature Communications ◽

10.1038/s41467-020-19823-5 ◽

2020 ◽

Vol 11 (1) ◽

Author(s):

Zhijun Xu ◽

Shengliang Wang ◽

Chunyu Zhao ◽

Shangsong Li ◽

Xiaoman Liu ◽

...

Keyword(s):

Hydrogen Production ◽

Self Assembly ◽

Spatial Organization ◽

Oxygen Depletion ◽

Bacterial Cells ◽

Multicellular Spheroids ◽

Two Phase ◽

Aerobic Conditions ◽

Micro Reactors ◽

And Function

AbstractThe spontaneous self-assembly of multicellular ensembles into living materials with synergistic structure and function remains a considerable challenge in biotechnology and synthetic biology. Here, we exploit the aqueous two-phase separation of dextran-in-PEG emulsion micro-droplets for the capture, spatial organization and immobilization of algal cells or algal/bacterial cell communities to produce discrete multicellular spheroids capable of both aerobic (oxygen producing) and hypoxic (hydrogen producing) photosynthesis in daylight under air. We show that localized oxygen depletion results in hydrogen production from the core of the algal microscale reactor, and demonstrate that enhanced levels of hydrogen evolution can be achieved synergistically by spontaneously enclosing the photosynthetic cells within a shell of bacterial cells undergoing aerobic respiration. Our results highlight a promising droplet-based environmentally benign approach to dispersible photosynthetic microbial micro-reactors comprising segregated cellular micro-niches with dual functionality, and provide a step towards photobiological hydrogen production under aerobic conditions.

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