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1.
Semin Cell Dev Biol ; 134: 90-102, 2023 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-35317961

RESUMO

Brown algae are a group of multicellular, heterokont algae that have convergently evolved developmental complexity that rivals that of embryophytes, animals or fungi. Early in development, brown algal zygotes establish a basal and an apical pole, which will become respectively the basal system (holdfast) and the apical system (thallus) of the adult alga. Brown algae are interesting models for understanding the establishment of cell polarity in a broad evolutionary context, because they exhibit a large diversity of life cycles, reproductive strategies and, importantly, their zygotes are produced in large quantities free of parental tissue, with symmetry breaking and asymmetric division taking place in a highly synchronous manner. This review describes the current knowledge about the establishment of the apical-basal axis in the model brown seaweeds Ectocarpus, Dictyota, Fucus and Saccharina, highlighting the advantages and specific interests of each system. Ectocarpus is a genetic model system that allows access to the molecular basis of early development and life-cycle control over apical-basal polarity. The oogamous brown alga Fucus, together with emerging comparative models Dictyota and Saccharina, emphasize the diversity of strategies of symmetry breaking in determining a cell polarity vector in brown algae. A comparison with symmetry-breaking mechanisms in land plants, animals and fungi, reveals that the one-step zygote polarisation of Fucus compares well to Saccharomyces budding and Arabidopsis stomata development, while the two-phased symmetry breaking in the Dictyota zygote compares to Schizosaccharomyces fission, the Caenorhabditis anterior-posterior zygote polarisation and Arabidopsis prolate pollen polarisation. The apical-basal patterning in Saccharina zygotes on the other hand, may be seen as analogous to that of land plants. Overall, brown algae have the potential to bring exciting new information on how a single cell gives rise to an entire complex body plan.


Assuntos
Arabidopsis , Feófitas , Animais , Zigoto , Feófitas/genética , Feófitas/metabolismo , Polaridade Celular , Divisão Celular , Plantas
2.
Semin Cell Dev Biol ; 133: 65-73, 2023 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-35307284

RESUMO

A ubiquitous feature of animal development is the formation of fluid-filled cavities or lumina, which transport gases and fluids across tissues and organs. Among different species, lumina vary drastically in size, scale, and complexity. However, all lumen formation processes share key morphogenetic principles that underly their development. Fundamentally, a lumen simply consists of epithelial cells that encapsulate a continuous internal space, and a common way of building a lumen is via opening and enlarging by filling it with fluid and/or macromolecules. Here, we discuss how polarized targeting of membrane and secreted proteins regulates lumen formation, mainly focusing on ion transporters in vertebrate model systems. We also discuss mechanistic differences observed among invertebrates and vertebrates and describe how the unique properties of the Na+/K+-ATPase and junctional proteins can promote polarization of immature epithelia to build lumina de novo in developing organs.


Assuntos
Células Epiteliais , Proteínas , Animais , Morfogênese/fisiologia , Epitélio , Células Epiteliais/metabolismo , Proteínas/metabolismo , Membrana Celular/metabolismo , Polaridade Celular/fisiologia
3.
J Cell Biol ; 222(2)2023 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-36409222

RESUMO

In Drosophila melanogaster, the anterior-posterior body axis is maternally established and governed by differential localization of partitioning defective (Par) proteins within the oocyte. At mid-oogenesis, Par-1 accumulates at the oocyte posterior end, while Par-3/Bazooka is excluded there but maintains its localization along the remaining oocyte cortex. Past studies have proposed the need for somatic cells at the posterior end to initiate oocyte polarization by providing a trigger signal. To date, neither the molecular identity nor the nature of the signal is known. Here, we provide evidence that mechanical contact of posterior follicle cells (PFCs) with the oocyte cortex causes the posterior exclusion of Bazooka and maintains oocyte polarity. We show that Bazooka prematurely accumulates exclusively where posterior follicle cells have been mechanically detached or ablated. Furthermore, we provide evidence that PFC contact maintains Par-1 and oskar mRNA localization and microtubule cytoskeleton polarity in the oocyte. Our observations suggest that cell-cell contact mechanics modulates Par protein binding sites at the oocyte cortex.


Assuntos
Proteínas de Drosophila , Drosophila melanogaster , Folículo Ovariano , Animais , Feminino , Padronização Corporal , Polaridade Celular , Drosophila melanogaster/genética , Drosophila melanogaster/fisiologia , Proteínas de Drosophila/genética , Proteínas de Drosophila/fisiologia , Quinase 3 da Glicogênio Sintase/genética , Quinase 3 da Glicogênio Sintase/fisiologia , Oócitos/fisiologia , Folículo Ovariano/citologia , Peptídeos e Proteínas de Sinalização Intracelular/genética , Peptídeos e Proteínas de Sinalização Intracelular/fisiologia
4.
Cell Rep ; 41(6): 111588, 2022 Nov 08.
Artigo em Inglês | MEDLINE | ID: mdl-36351382

RESUMO

Claudins are a family of transmembrane proteins expressed in epithelial tissues and are the major components of tight junctions (TJs), which define barrier properties in epithelia and maintain cell polarity. How claudins regulate the formation of TJs and which functions they exert outside of them is not entirely understood. Although the long and unstructured C-terminal tail is essential for regulation, it is unclear how it is involved in these functions beyond interacting with TJ-associated proteins such as TJ protein ZO-1 (TJP1). Here, we present an interactome study of the pan-claudin family in Madin-Darby canine kidney (MDCK)-C7 cells by combining two complementary mass spectrometry-based pull-down techniques creating an interaction landscape of the entire claudin family. The interaction partners of the claudins' C termini reveal their possible implications in localized biological processes in epithelial cells and their regulation by post-translational modifications (PTMs).


Assuntos
Claudinas , Junções Íntimas , Cães , Animais , Claudinas/metabolismo , Linhagem Celular , Junções Íntimas/metabolismo , Células Madin Darby de Rim Canino , Polaridade Celular
5.
Sci Adv ; 8(44): eabo2343, 2022 11 04.
Artigo em Inglês | MEDLINE | ID: mdl-36332030

RESUMO

The polarization of neurons into axons and dendrites depends on extracellular cues, intracellular signaling, cytoskeletal rearrangements, and polarized transport, but the interplay between these processes during polarization remains unresolved. Here, we show that axon specification is determined by differences in microtubule network mobility between neurites, regulated by Rho guanosine triphosphatases (GTPases) and extracellular cues. In developing neurons, retrograde microtubule flow prevents the entry of the axon-selective motor protein Kinesin-1 into most neurites. Using inducible assays to control microtubule network flow, we demonstrate that local inhibition of microtubule mobility is sufficient to guide Kinesin-1 into a specific neurite, whereas long-term global inhibition induces the formation of multiple axons. We furthermore show that extracellular mechanical cues and intracellular Rho GTPase signaling control the local differences in microtubule network flow. These results reveal a novel cytoskeletal mechanism for neuronal polarization.


Assuntos
Hipocampo , Cinesinas , Hipocampo/metabolismo , Polaridade Celular/fisiologia , Células Cultivadas , Axônios/metabolismo , Neurônios/fisiologia , Microtúbulos/metabolismo
6.
Dev Cell ; 57(21): 2483-2496.e4, 2022 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-36347240

RESUMO

Collective cell movements drive normal development and metastasis. Drosophila border cells move as a cluster of 6-10 cells, where the role of the Rac GTPase in migration was first established. In border cells, as in most migratory cells, Rac stimulates leading-edge protrusion. Upstream Rac regulators in leaders have been identified; however, the regulation and function of Rac in follower border cells is unknown. Here, we show that all border cells require Rac, which promotes follower-cell motility and is important for cluster compactness and movement. We identify a Rac guanine nucleotide exchange factor, Cdep, which also regulates follower-cell movement and cluster cohesion. Scribble, Discs large, and Lethal giant larvae localize Cdep basolaterally and share phenotypes with Cdep. Relocalization of Cdep::GFP partially rescues Scribble knockdown, suggesting that Cdep is a major downstream effector of basolateral proteins. Thus, a Scrib/Cdep/Rac pathway promotes cell crawling and coordinated, collective migration in vivo.


Assuntos
Proteínas de Drosophila , Drosophila , Animais , Movimento Celular/fisiologia , Drosophila/metabolismo , Piperazinas/metabolismo , Oogênese , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Polaridade Celular/fisiologia
7.
Results Probl Cell Differ ; 70: 597-606, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36348123

RESUMO

Polarity is an intrinsic and fundamental property of unicellular organisms and, as well, of single cells in multicellular ones. It can be defined as asymmetric cell organization that is self-reinforced and maintained by appropriate signaling. While cellular polarity is widely studied at the membrane and cytoplasmic level, if and how it is transmitted to the nucleus is still a matter of research and discussion. However, there is growing evidence of polarity transmission from the cell to the nucleus. In this chapter, we discuss recent reports on nuclear polarity and involvement of potential molecular players including emerin, nesprins, and nuclear F-actin which may play a significant role in establishment of this phenomenon.


Assuntos
Proteínas dos Microfilamentos , Membrana Nuclear , Membrana Nuclear/metabolismo , Proteínas dos Microfilamentos/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Núcleo Celular , Polaridade Celular
8.
Development ; 149(22)2022 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-36325991

RESUMO

In the developing hindbrain, facial branchiomotor (FBM) neurons migrate caudally from rhombomere 4 (r4) to r6 to establish the circuit that drives jaw movements. Although the mechanisms regulating initiation of FBM neuron migration are well defined, those regulating directionality are not. In mutants lacking the Wnt/planar cell polarity (PCP) component Celsr1, many FBM neurons inappropriately migrate rostrally into r3. We hypothesized that Celsr1 normally blocks inappropriate rostral migration of FBM neurons by suppressing chemoattraction towards Wnt5a in r3 and successfully tested this model. First, FBM neurons in Celsr1; Wnt5a double mutant embryos never migrated rostrally, indicating that inappropriate rostral migration in Celsr1 mutants results from Wnt5a-mediated chemoattraction, which is suppressed in wild-type embryos. Second, FBM neurons migrated rostrally toward Wnt5a-coated beads placed in r3 of wild-type hindbrain explants, suggesting that excess Wnt5a chemoattractant can overcome endogenous Celsr1-mediated suppression. Third, rostral migration of FBM neurons was greatly enhanced in Celsr1 mutants overexpressing Wnt5a in r3. These results reveal a novel role for a Wnt/PCP component in regulating neuronal migration through suppression of chemoattraction.


Assuntos
Regulação da Expressão Gênica no Desenvolvimento , Neurônios Motores , Neurônios Motores/fisiologia , Rombencéfalo , Polaridade Celular , Movimento Celular/genética
9.
Cell Mol Life Sci ; 79(12): 586, 2022 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-36369349

RESUMO

Gastrulation and neurulation are successive morphogenetic processes that play key roles in shaping the basic embryonic body plan. Importantly, they operate through common cellular and molecular mechanisms to set up the three spatially organized germ layers and to close the neural tube. During gastrulation and neurulation, convergent extension movements driven by cell intercalation and oriented cell division generate major forces to narrow the germ layers along the mediolateral axis and elongate the embryo in the anteroposterior direction. Apical constriction also makes an important contribution to promote the formation of the blastopore and the bending of the neural plate. Planar cell polarity proteins are major regulators of asymmetric cell behaviors and critically involved in a wide variety of developmental processes, from gastrulation and neurulation to organogenesis. Mutations of planar cell polarity genes can lead to general defects in the morphogenesis of different organs and the co-existence of distinct congenital diseases, such as spina bifida, hearing deficits, kidney diseases, and limb elongation defects. This review outlines our current understanding of non-canonical Wnt signaling, commonly known as Wnt/planar cell polarity signaling, in regulating morphogenetic movements of gastrulation and neural tube closure during development and disease. It also attempts to identify unanswered questions that deserve further investigations.


Assuntos
Defeitos do Tubo Neural , Neurulação , Humanos , Neurulação/genética , Gastrulação/genética , Polaridade Celular/genética , Via de Sinalização Wnt/genética , Tubo Neural/metabolismo , Morfogênese/genética , Defeitos do Tubo Neural/genética , Defeitos do Tubo Neural/metabolismo
10.
Fly (Austin) ; 16(1): 367-381, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36413374

RESUMO

Cell-cell interactions within tumour microenvironment play crucial roles in tumorigenesis. Genetic mosaic techniques available in Drosophila have provided a powerful platform to study the basic principles of tumour growth and progression via cell-cell communications. This led to the identification of oncogenic cell-cell interactions triggered by endocytic dysregulation, mitochondrial dysfunction, cell polarity defects, or Src activation in Drosophila imaginal epithelia. Such oncogenic cooperations can be caused by interactions among epithelial cells, mesenchymal cells, and immune cells. Moreover, microenvironmental factors such as nutrients, local tissue structures, and endogenous growth signalling activities critically affect tumorigenesis. Dissecting various types of oncogenic cell-cell interactions at the single-cell level in Drosophila will greatly increase our understanding of how tumours progress in living animals.


Assuntos
Comunicação Celular , Drosophila , Animais , Carcinogênese , Transdução de Sinais , Polaridade Celular , Microambiente Tumoral
11.
Nat Cell Biol ; 24(11): 1606-1616, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36302967

RESUMO

Asymmetric cell division gives rise to two daughter cells that inherit different determinants, thereby acquiring different fates. Polarized trafficking of endosomes containing fate determinants recently emerged as an evolutionarily conserved feature of asymmetric cell division to enhance the robustness of asymmetric cell fate determination in flies, fish and mammals. In particular, polarized sorting of signalling endosomes by an asymmetric central spindle contributes to asymmetric cell division in Drosophila melanogaster. However, how central spindle asymmetry arises remains elusive. Here we identify a moonlighting function of the Elongator complex-an established protein acetylase and tRNA methylase involved in the fidelity of protein translation-as a key factor for central spindle asymmetry. Elongator controls spindle asymmetry by stabilizing microtubules differentially on the anterior side of the central spindle. Accordingly, lowering the activity of Elongator on the anterior side using nanobodies mistargets endosomes to the wrong cell. Molecularly, Elongator regulates microtubule dynamics independently of its acetylation and methylation enzymatic activities. Instead, Elongator directly binds to microtubules and increases their polymerization speed while decreasing their catastrophe frequency. Our data establish a non-canonical role of Elongator at the core of cytoskeleton polarity and asymmetric signalling.


Assuntos
Drosophila melanogaster , Fuso Acromático , Animais , Fuso Acromático/metabolismo , Microtúbulos/metabolismo , Divisão Celular Assimétrica , Endossomos/metabolismo , Polaridade Celular , Mamíferos
12.
Development ; 149(22)2022 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-36305473

RESUMO

The polarity of mouse hair follicles is controlled by the Frizzled (Fzd) receptors and other membrane planar cell polarity (PCP) proteins. Whether Wnt proteins can act as PCP ligands in the skin remains unknown. Here, we show that overexpression of Wnt5a in the posterior part of mouse embryos causes a local disruption of hair follicle orientation. The misoriented hair follicle phenotype in Wnt5a overexpressing mice can be rescued by a heterozygous loss of Fzd6, suggesting Wnt5a is likely to signal through Fzd6. Although the membrane distribution of PCP proteins seems unaffected by Wnt5a overexpression, transcriptional profiling analyses identify a set of genes as potential targets of the skin polarization program controlled by Wnt5a/Fzd6 signaling. Surprisingly, deletion of Wnt5a globally or in the posterior part of the mouse embryos does not affect hair follicle orientation. We show that many other Wnts are highly expressed in the developing skin. They can activate the Fzd6 signaling pathway in vitro and may act together with Wnt5a to regulate the Fzd6-mediated skin polarization. Our experiments demonstrate for the first time that Wnt5a can function as an orienting cue for mouse skin PCP.


Assuntos
Folículo Piloso , Proteínas Wnt , Camundongos , Animais , Folículo Piloso/metabolismo , Proteína Wnt-5a/genética , Proteína Wnt-5a/metabolismo , Proteínas Wnt/genética , Proteínas Wnt/metabolismo , Transdução de Sinais/genética , Polaridade Celular/genética , Pele/metabolismo
14.
PLoS Biol ; 20(10): e3001834, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-36223339

RESUMO

Neural stem cells (NSCs) divide asymmetrically to balance their self-renewal and differentiation, an imbalance in which can lead to NSC overgrowth and tumor formation. The functions of Parafibromin, a conserved tumor suppressor, in the nervous system are not established. Here, we demonstrate that Drosophila Parafibromin/Hyrax (Hyx) inhibits ectopic NSC formation by governing cell polarity. Hyx is essential for the asymmetric distribution and/or maintenance of polarity proteins. hyx depletion results in the symmetric division of NSCs, leading to the formation of supernumerary NSCs in the larval brain. Importantly, we show that human Parafibromin rescues the ectopic NSC phenotype in Drosophila hyx mutant brains. We have also discovered that Hyx is required for the proper formation of interphase microtubule-organizing center and mitotic spindles in NSCs. Moreover, Hyx is required for the proper localization of 2 key centrosomal proteins, Polo and AurA, and the microtubule-binding proteins Msps and D-TACC in dividing NSCs. Furthermore, Hyx directly regulates the polo and aurA expression in vitro. Finally, overexpression of polo and aurA could significantly suppress ectopic NSC formation and NSC polarity defects caused by hyx depletion. Our data support a model in which Hyx promotes the expression of polo and aurA in NSCs and, in turn, regulates cell polarity and centrosome/microtubule assembly. This new paradigm may be relevant to future studies on Parafibromin/HRPT2-associated cancers.


Assuntos
Proteínas de Drosophila , Células-Tronco Neurais , Animais , Polaridade Celular , Centrossomo/metabolismo , Drosophila/metabolismo , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Humanos , Células-Tronco Neurais/metabolismo , Fatores de Transcrição/metabolismo
15.
Curr Biol ; 32(22): 4967-4974.e5, 2022 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-36257315

RESUMO

Many plant cells exhibit polarity, revealed by asymmetric localization of specific proteins within each cell.1,2,3,4,5,6 Polarity is typically coordinated between cells across a tissue, raising the question of how coordination is achieved. One hypothesis is that mechanical stresses provide cues.7 This idea gains support from experiments in which cotyledons were mechanically stretched transversely to their midline.8 These previously published results showed that without applied tension, the stomatal lineage cell polarity marker, BREVIS RADIX-LIKE 2 (BRXL2), exhibited no significant excess in the transverse orientation. By contrast, 7 h after stretching, BRXL2 polarity distribution exhibited transverse excess, aligned with the stretch direction. These stretching experiments involved statistical comparisons between snapshots of stretched and unstretched cotyledons, with different specimens being imaged in each case.8 Here, we image the same cotyledon before and after stretching and find no evidence for reorientation of polarity. Instead, statistical analysis shows that cotyledons contain a pre-existing transverse excess in BRXL2 polarity orientation that is not significantly modified by applied tension. The transverse excess reflects BRLX2 being preferentially localized toward the medial side of the cell, nearer to the cotyledon midline, creating a weak medial bias. A second polarity marker, BREAKING OF ASYMMETRY IN THE STOMATAL LINEAGE (BASL), also exhibits weak medial bias in stomatal lineages, whereas ectopic expression of BASL in non-stomatal cells exhibits strong proximal bias, as previously observed in rosette leaves. This proximal bias is also unperturbed by applied tension. Our findings therefore show that cotyledons contain two near-orthogonal coordinated biases in planar polarity: mediolateral and proximodistal.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Arabidopsis/genética , Arabidopsis/metabolismo , Cotilédone , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Estômatos de Plantas/metabolismo , Folhas de Planta/metabolismo , Polaridade Celular , Linhagem da Célula , Proteínas de Ciclo Celular/metabolismo
16.
Nat Cell Biol ; 24(10): 1499-1515, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-36202973

RESUMO

During cell migration and polarization, numerous signal transduction and cytoskeletal components self-organize to generate localized protrusions. Although biochemical and genetic analyses have delineated many specific interactions, how the activation and localization of so many different molecules are spatiotemporally orchestrated at the subcellular level has remained unclear. Here we show that the regulation of negative surface charge on the inner leaflet of the plasma membrane plays an integrative role in the molecular interactions. Surface charge, or zeta potential, is transiently lowered at new protrusions and within cortical waves of Ras/PI3K/TORC2/F-actin network activation. Rapid alterations of inner leaflet anionic phospholipids-such as PI(4,5)P2, PI(3,4)P2, phosphatidylserine and phosphatidic acid-collectively contribute to the surface charge changes. Abruptly reducing the surface charge by recruiting positively charged optogenetic actuators was sufficient to trigger the entire biochemical network, initiate de novo protrusions and abrogate pre-existing polarity. These effects were blocked by genetic or pharmacological inhibition of key signalling components such as AKT and PI3K/TORC2. Conversely, increasing the negative surface charge deactivated the network and locally suppressed chemoattractant-induced protrusions or subverted EGF-induced ERK activation. Computational simulations involving excitable biochemical networks demonstrated that slight changes in feedback loops, induced by recruitment of the charged actuators, could lead to outsized effects on system activation. We propose that key signalling network components act on, and are in turn acted upon, by surface charge, closing feedback loops, which bring about the global-scale molecular self-organization required for spontaneous protrusion formation, cell migration and polarity establishment.


Assuntos
Actinas , Polaridade Celular , Polaridade Celular/fisiologia , Actinas/metabolismo , Fosfatidilserinas/metabolismo , Fator de Crescimento Epidérmico , Proteínas Proto-Oncogênicas c-akt/genética , Proteínas Proto-Oncogênicas c-akt/metabolismo , Movimento Celular , Membrana Celular/metabolismo , Fosfatidilinositol 3-Quinases/genética , Fosfatidilinositol 3-Quinases/metabolismo , Alvo Mecanístico do Complexo 2 de Rapamicina/metabolismo , Fatores Quimiotáticos/metabolismo
17.
Dev Cell ; 57(19): 2321-2333.e9, 2022 10 10.
Artigo em Inglês | MEDLINE | ID: mdl-36220082

RESUMO

Blood-vessel formation generates unique vascular patterns in each individual. The principles governing the apparent stochasticity of this process remain to be elucidated. Using mathematical methods, we find that the transition between two fundamental vascular morphogenetic programs-sprouting angiogenesis and vascular remodeling-is established by a shift of collective front-to-rear polarity of endothelial cells in the mouse retina. We demonstrate that the competition between biochemical (VEGFA) and mechanical (blood-flow-induced shear stress) cues controls this collective polarity shift. Shear stress increases tension at focal adhesions overriding VEGFA-driven collective polarization, which relies on tension at adherens junctions. We propose that vascular morphogenetic cues compete to regulate individual cell polarity and migration through tension shifts that translates into tissue-level emergent behaviors, ultimately leading to uniquely organized vascular patterns.


Assuntos
Polaridade Celular , Células Endoteliais , Junções Aderentes/metabolismo , Animais , Movimento Celular/fisiologia , Polaridade Celular/fisiologia , Células Endoteliais/metabolismo , Camundongos , Morfogênese , Retina/metabolismo
18.
Analyst ; 147(22): 5231-5238, 2022 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-36278807

RESUMO

Polarity and viscosity, as important microenvironment parameters, play an essential role in cell metabolism. Therefore, 9-acridine carboxaldehyde reacted with cyano compounds to obtain polarity-sensitive probes 1a-b and viscosity-sensitive probes 1c-d. Among them, with the increase in solvent polarity, the maximum emission wavelength of acridine-dicyanoisophorone-based probe 1a red-shifted from 553 nm to 594 nm, the fluorescence quantum yield increased from 0.5% to 35.6%, and the fluorescence intensity enhanced 38 fold. The acridine-cyanofuranone based probe 1b also has a polarity response similar to 1a. Nevertheless, when the solution viscosity increased from 0.89 cP (100% water) to 856 cP (1% water), the fluorescence intensity of the acridine-tricyanodihydrofuran based probe 1c at 430 nm enhanced 5.6 times. The acridine-cyanobenzothiazole based probe 1d also had a viscosity response similar to 1c. In addition, probes 1a-b were used for further HeLa cell imaging experiments due to their good photostability and the results suggested that probe 1a could locate lipid droplets and probes 1b-c could stain lysosomes. Moreover, probes 1a-b could dynamically monitor the changes in intracellular polarity.


Assuntos
Polaridade Celular , Corantes Fluorescentes , Humanos , Espectrometria de Fluorescência , Células HeLa , Substâncias Intercalantes , Água , Viscosidade , Acridinas
19.
Exp Cell Res ; 421(2): 113387, 2022 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-36252648

RESUMO

Rack1 features seven WD40 repeats that fold into a multifaceted scaffold used to build signaling complexes in a context-dependent manner. Previous in vitro studies have revealed associations between Rack1 and many other proteins. Rack 1 is required for establishing planar cell polarity (PCP) in zebrafish and Xenopus. However, any molecular role of Rack1 in protein complexes or polarity regulation remains unclear. Here, we show that Rack1 is an essential gene in mice. Conditional knockout of Rack1 shortened the cochlear duct and induced cellular patterning defects characteristic of defective convergent extension (this PCP process is mediated by cellular junctional remodeling in the developing cochlear epithelium). Also, cochlear hair cells were no longer uniformly oriented in Rack1 conditional knockout mutants. Rack1 was enriched in the cellular cortices of sensory hair cells. In Rack1-deficient cochleae, E-cadherin expression at the cellular boundaries was greatly reduced. Together, the findings reveal a molecular role of Rack1 in PCP signaling that likely involves modulation of E-cadherin levels at the adherens junctions of the plasma membrane.


Assuntos
Polaridade Celular , Peixe-Zebra , Camundongos , Animais , Polaridade Celular/genética , Cóclea/metabolismo , Morfogênese , Caderinas/genética , Caderinas/metabolismo , Receptores de Quinase C Ativada/genética , Receptores de Quinase C Ativada/metabolismo
20.
Development ; 149(22)2022 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-36264257

RESUMO

Apico-basolateral polarization is essential for epithelial cells to function as selective barriers and transporters, and to provide mechanical resilience to organs. Epithelial polarity is established locally, within individual cells to establish distinct apical, junctional and basolateral domains, and globally, within a tissue where cells coordinately orient their apico-basolateral axes. Using live imaging of endogenously tagged proteins and tissue-specific protein depletion in the Caenorhabditiselegans embryonic intestine, we found that local and global polarity establishment are temporally and genetically separable. Local polarity is initiated prior to global polarity and is robust to perturbation. PAR-3 is required for global polarization across the intestine but local polarity can arise in its absence, as small groups of cells eventually established polarized domains in PAR-3-depleted intestines in a HMR-1 (E-cadherin)-dependent manner. Despite the role of PAR-3 in localizing PKC-3 to the apical surface, we additionally found that PAR-3 and PKC-3/aPKC have distinct roles in the establishment and maintenance of local and global polarity. Taken together, our results indicate that different mechanisms are required for local and global polarity establishment in vivo.


Assuntos
Polaridade Celular , Células Epiteliais , Células Epiteliais/metabolismo , Junções Intercelulares , Mucosa Intestinal , Intestinos , Epitélio
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