scholarly journals The Rilp-like proteins Rilpl1 and Rilpl2 regulate ciliary membrane content

2013 ◽  
Vol 24 (4) ◽  
pp. 453-464 ◽  
Author(s):  
Johanna R. Schaub ◽  
Tim Stearns
Keyword(s):  
Primary Cilium ◽  
Protein Localization ◽  
Three Dimensional ◽  
Cell Types ◽  
Ciliary Membrane ◽  
Tracheal Epithelial Cells ◽  
Mother Centriole ◽  
Cell Organization ◽  
Regulate Protein ◽  
Related Proteins

The primary cilium is a microtubule-based structure found in most cell types in mammals. Disruption of cilium function causes a diverse set of human diseases collectively known as ciliopathies. We report that Rab effector–related proteins Rab-interacting lysosomal protein-like 1 (Rilpl1) and Rilpl2 regulate protein localization in the primary cilium. Rilpl2 was initially identified as up-regulated in ciliating mouse tracheal epithelial cells. Rilpl1 and Rilpl2 both localize to the primary cilium and centrosome, Rilpl1 specifically to the distal end of the mother centriole. Live-cell microscopy reveals that Rilpl2 primary cilium localization is dynamic and that it is associated with tubulovesicular structures at the base of the cilium. Depletion of Rilpl1 and Rilpl2 results in accumulation of signaling proteins in the ciliary membrane and prevents proper epithelial cell organization in three-dimensional culture. These data suggest that Rilp-like proteins function in regulation of ciliary membrane protein concentration by promoting protein removal from the primary cilium.

scholarly journals THE FINE STRUCTURE OF CORTICAL COMPONENTS OF PARAMECIUM MULTIMICRONUCLEATUM

1955 ◽  
Vol 1 (6) ◽  
pp. 583-604 ◽  
Author(s):  
Albert W. Sedar ◽  
Keith R. Porter
Keyword(s):  
Plasma Membrane ◽  
Fine Structure ◽  
Basal Body ◽  
Three Dimensional ◽  
Cell Types ◽  
The Body ◽  
Fiber System ◽  
Thin Sections ◽  
Ciliary Membrane ◽  
The Matrix

The electron microscope was used to study the structure and three dimensional relationships of the components of the body cortex in thin sections of Paramecium multimicronucleatum. Micrographs of sections show that the cortex is covered externally by two closely apposed membranes (together ∼250 A thick) constituting the pellicle. Beneath the pellicle the surface of the animal is molded into ridges that form a polygonal ridgework with depressed centers. It is these ridges that give the surface of the organism its characteristic configuration and correspond to the outer fibrillar system of the light microscope image. The outer ends of the trichocysts with their hood-shaped caps are located in the centers of the anterior and posterior ridges of each polygon. The cilia extend singly from the depressed centers of the surface polygons. Each cilium shows two axial filaments with 9 peripheral and parallel filaments embedded in a matrix and the whole surrouned by a thin ciliary membrane. The 9 peripheral filaments are double and these are evenly spaced in a circle around the central pair. The ciliary membrane is continuous with the outer member of the pellicular membrane, whereas the plasma membrane is continuous with the inner member of the pellicular membrane. At the level of the plasma membrane the proximal end of the cilium is continuous with its tube-shaped basal body or kinetosome. The peripheral filaments of the cilium, together with the material of cortical matrix which tends to condense around them, form the sheath of the basal body. The kinetodesma connecting the ciliary kinetosomes (inner fibrillar system of the light microscopist) is composed of a number of discrete fibrils which overlap in a shingle-like fashion. Each striated kinetosomal fibril originates from a ciliary kinetosome and runs parallel to other kinetosomal fibrils arising from posterior kinetosomes of a particular meridional array. Sections at the level of the ciliary kinetosomes reveal an additional fiber system, the infraciliary lattice system, which is separate and distinct from the kinetodesmal system. This system consists of a fibrous network of irregular polygons and runs roughly parallel to the surface of the animal. Mitochondria have a fine structure similar in general features to that described for a number of mammalian cell types, but different in certain details. The structures corresponding to cristae mitochondriales appear as finger-like projections or microvilli extending into the matrix of the organelle from the inner membrane of the paired mitochondrial membrane. The cortical cytoplasm contains also a particulate component and a system of vesicles respectively comparable to the nucleoprotein particles and to the endoplasmic reticulum described in various metazoan cell types. An accessory kinetosome has been observed in oblique sections of a number of non-dividing specimens slightly removed from the ciliary kinetosome and on the same meridional line as the cilia and trichocysts. Its position corresponds to the location of the kinetosome of the newly formed cilium in animals selected as being in the approaching fission stage of the life cycle.

scholarly journals The ciliary membrane of polarized epithelial cells stems from a midbody remnant-associated membrane patch with condensed nanodomains

2019 ◽  
Author(s):  
Miguel Bernabé-Rubio ◽  
Minerva Bosch-Fortea ◽  
Esther García ◽  
Jorge Bernardino de la Serna ◽  
Miguel A. Alonso
Keyword(s):  
Plasma Membrane ◽  
Epithelial Cells ◽  
Primary Cilium ◽  
Mdck Cells ◽  
Cell Types ◽  
Apical Surface ◽  
Cellular Behavior ◽  
Ciliary Membrane ◽  
Lipid Dynamics

AbstractThe primary cilium is a specialized plasma membrane protrusion that harbors receptors involved in important signaling pathways. Despite its central role in regulating cellular behavior, the biogenesis of the primary cilium is not fully understood. In fact, the source of the ciliary membrane remains a mystery in cell types that assemble their primary cilium entirely at the cell surface, such as polarized renal epithelial cells. After cytokinesis, the remnant of the midbody of these cells moves to the center of the apical surface, where it licenses the centrosome for ciliogenesis through an unidentified mechanism. Here, to investigate the origin of the ciliary membrane and the role of the midbody remnant, we analyzed membrane compaction and lipid dynamics at the microscale and nanoscale in living renal epithelial MDCK cells. We found that a specialized patch made of condensed membranes with restricted lipid lateral mobility surrounds the midbody remnant. This patch accompanies the remnant on its journey towards the centrosome and, once the two structures have met, the remnant delivers part of membranes of the patch to build the ciliary membrane. In this way, we have determined the origin of the ciliary membrane and the contribution of the midbody remnant to primary cilium formation in cells whose primary cilium is assembled at the plasma membrane.

scholarly journals EFA6A, an exchange factor for Arf6, regulates early steps in ciliogenesis

2021 ◽  
Vol 134 (2) ◽  
pp. jcs249565
Author(s):  
Mariagrazia Partisani ◽  
Carole L. Baron ◽  
Rania Ghossoub ◽  
Racha Fayad ◽  
Sophie Pagnotta ◽  
...  
Keyword(s):  
G Protein ◽  
Primary Cilium ◽  
Early Stage ◽  
Ciliary Membrane ◽  
Exchange Factor ◽  
Small G Protein ◽  
Mother Centriole

ABSTRACTCiliogenesis is a coordinated process initiated by the recruitment and fusion of pre-ciliary vesicles at the distal appendages of the mother centriole through mechanisms that remain unclear. Here, we report that EFA6A (also known as PSD), an exchange factor for the small G protein Arf6, is involved in early stage of ciliogenesis by promoting the fusion of distal appendage vesicles forming the ciliary vesicle. EFA6A is present in the vicinity of the mother centriole before primary cilium assembly and prior to the arrival of Arl13B-containing vesicles. During ciliogenesis, EFA6A initially accumulates at the mother centriole and later colocalizes with Arl13B along the ciliary membrane. EFA6A depletion leads to the inhibition of ciliogenesis, the absence of centrosomal Rab8-positive structures and the accumulation of Arl13B-positive vesicles around the distal appendages. Our results uncover a novel fusion machinery, comprising EFA6A, Arf6 and Arl13B, that controls the coordinated fusion of ciliary vesicles docked at the distal appendages of the mother centriole.

SEM of Hepatocytes and Biliary Passages in Goldfish Liver

1977 ◽  
Vol 35 ◽  
pp. 556-557
Author(s):  
Waykin Nopanitaya ◽  
Joe W. Grisham ◽  
Johnny L. Carson
Keyword(s):  
Carassius Auratus ◽  
Cell Layer ◽  
Three Dimensional ◽  
Cell Types ◽  
Biliary System ◽  
Fish Food ◽  
Commercial Fish ◽  
Goldfish Carassius Auratus ◽  
Commercial Fish Food

An interesting feature of the goldfish liver is the morphology of the hepatic plate, which is always formed by a two-cell layer of hepatocytes. Hepatic plates of the goldfish liver contain an infrequently seen second type of cell, in the centers of plates between two hepatocytes. A TEH study by Yamamoto (1) demonstrated ultrastructural differences between hepatocytes and centrally located cells in hepatic plates; the latter were classified as ductule cells of the biliary system. None of the previous studies clearly showed a three-dimensional organization of the two cell types described. In the present investigation we utilize SEM to elucidate the arrangement of hepatocytes and bile ductular cells in intralobular plates of goldfish liver.Livers from young goldfish (Carassius auratus), about 6-10 cm, fed commercial fish food were used for this study. Hepatic samples were fixed in 4% buffered paraformaldehyde, cut into pieces, fractured, osmicated, CPD, mounted Au-Pd coated, and viewed by SEM at 17-20 kV. Our observations were confined to the ultrastructure of biliary passages within intralobular plates, ductule cells, and hepatocytes.

Three-dimensional image analysis and visualization in confocal light microscopy

1993 ◽  
Vol 51 ◽  
pp. 158-159
Author(s):  
J. K. Samarabandu ◽  
R. Acharya ◽  
D. R. Pareddy ◽  
P. C. Cheng
Keyword(s):  
Depth Perception ◽  
Computer Graphic ◽  
Three Dimensional ◽  
Cellular Organization ◽  
Data Set ◽  
Computational Burden ◽  
Interactive Operation ◽  
Cell Organization ◽  
Confocal Images ◽  
3D Digitization

In the study of cell organization in a maize meristem, direct viewing of confocal optical sections in 3D (by means of 3D projection of the volumetric data set, Figure 1) becomes very difficult and confusing because of the large number of nucleus involved. Numerical description of the cellular organization (e.g. position, size and orientation of each structure) and computer graphic presentation are some of the solutions to effectively study the structure of such a complex system. An attempt at data-reduction by means of manually contouring cell nucleus in 3D was reported (Summers et al., 1990). Apart from being labour intensive, this 3D digitization technique suffers from the inaccuracies of manual 3D tracing related to the depth perception of the operator. However, it does demonstrate that reducing stack of confocal images to a 3D graphic representation helps to visualize and analyze complex tissues (Figure 2). This procedure also significantly reduce computational burden in an interactive operation.

Epithelial Organotypic Cultures: A Viable Model to Address Mechanisms of Carcinogenesis by Epitheliotropic Viruses

2018 ◽  
Vol 18 (4) ◽  
pp. 246-255 ◽  
Author(s):  
Lara Termini ◽  
Enrique Boccardo
Keyword(s):  
Three Dimensional ◽  
Cell Types ◽  
Experimental Models ◽  
Biological Research ◽  
Specific Gene ◽  
Specific Cell ◽  
Organotypic Cultures ◽  
Skin Physiology

In vitro culture of primary or established cell lines is one of the leading techniques in many areas of basic biological research. The use of pure or highly enriched cultures of specific cell types obtained from different tissues and genetics backgrounds has greatly contributed to our current understanding of normal and pathological cellular processes. Cells in culture are easily propagated generating an almost endless source of material for experimentation. Besides, they can be manipulated to achieve gene silencing, gene overexpression and genome editing turning possible the dissection of specific gene functions and signaling pathways. However, monolayer and suspension cultures of cells do not reproduce the cell type diversity, cell-cell contacts, cell-matrix interactions and differentiation pathways typical of the three-dimensional environment of tissues and organs from where they were originated. Therefore, different experimental animal models have been developed and applied to address these and other complex issues in vivo. However, these systems are costly and time consuming. Most importantly the use of animals in scientific research poses moral and ethical concerns facing a steadily increasing opposition from different sectors of the society. Therefore, there is an urgent need for the development of alternative in vitro experimental models that accurately reproduce the events observed in vivo to reduce the use of animals. Organotypic cultures combine the flexibility of traditional culture systems with the possibility of culturing different cell types in a 3D environment that reproduces both the structure and the physiology of the parental organ. Here we present a summarized description of the use of epithelial organotypic for the study of skin physiology, human papillomavirus biology and associated tumorigenesis.

scholarly journals Relationship between sequence conservation and three-dimensional structure in a large family of esterases, lipases, and related proteins

1993 ◽  
Vol 2 (3) ◽  
pp. 366-382 ◽  
Author(s):  
Miroslaw Cygler ◽  
Joseph D. Schrag ◽  
Joel L. Sussman ◽  
Michal Harel ◽  
Israel Silman ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Large Family ◽  
Sequence Conservation ◽  
Dimensional Structure ◽  
Three Dimensional Structure ◽  
Related Proteins

scholarly journals Analysis of the transcriptome of bovine endometrial cells isolated by laser micro-dissection (1): specific signatures of stromal, glandular and luminal epithelial cells

BMC Genomics ◽  
2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Wiruntita Chankeaw ◽  
Sandra Lignier ◽  
Christophe Richard ◽  
Theodoros Ntallaris ◽  
Mariam Raliou ◽  
...  
Keyword(s):  
Gene Expression ◽  
Protein Localization ◽  
Expression Profiles ◽  
Cell Types ◽  
Molecular Signature ◽  
Receptor Protein ◽  
Specific Gene ◽  
Specific Cell ◽  
Biological Processes ◽  
Endometrial Cells

Abstract Background A number of studies have examined mRNA expression profiles of bovine endometrium at estrus and around the peri-implantation period of pregnancy. However, to date, these studies have been performed on the whole endometrium which is a complex tissue. Consequently, the knowledge of cell-specific gene expression, when analysis performed with whole endometrium, is still weak and obviously limits the relevance of the results of gene expression studies. Thus, the aim of this study was to characterize specific transcriptome of the three main cell-types of the bovine endometrium at day-15 of the estrus cycle. Results In the RNA-Seq analysis, the number of expressed genes detected over 10 transcripts per million was 6622, 7814 and 8242 for LE, GE and ST respectively. ST expressed exclusively 1236 genes while only 551 transcripts were specific to the GE and 330 specific to LE. For ST, over-represented biological processes included many regulation processes and response to stimulus, cell communication and cell adhesion, extracellular matrix organization as well as developmental process. For GE, cilium organization, cilium movement, protein localization to cilium and microtubule-based process were the only four main biological processes enriched. For LE, over-represented biological processes were enzyme linked receptor protein signaling pathway, cell-substrate adhesion and circulatory system process. Conclusion The data show that each endometrial cell-type has a distinct molecular signature and provide a significantly improved overview on the biological process supported by specific cell-types. The most interesting result is that stromal cells express more genes than the two epithelial types and are associated with a greater number of pathways and ontology terms.

scholarly journals Human iPSC-Based Modeling of Central Nerve System Disorders for Drug Discovery

2021 ◽  
Vol 22 (3) ◽  
pp. 1203
Author(s):  
Lu Qian ◽  
Julia TCW
Keyword(s):  
Drug Discovery ◽  
Disease Modeling ◽  
Three Dimensional ◽  
Structural Complexity ◽  
Induced Pluripotent Stem Cell ◽  
Cell Types ◽  
Central Nerve System ◽  
Human Ipscs ◽  
Nerve System

A high-throughput drug screen identifies potentially promising therapeutics for clinical trials. However, limitations that persist in current disease modeling with limited physiological relevancy of human patients skew drug responses, hamper translation of clinical efficacy, and contribute to high clinical attritions. The emergence of induced pluripotent stem cell (iPSC) technology revolutionizes the paradigm of drug discovery. In particular, iPSC-based three-dimensional (3D) tissue engineering that appears as a promising vehicle of in vitro disease modeling provides more sophisticated tissue architectures and micro-environmental cues than a traditional two-dimensional (2D) culture. Here we discuss 3D based organoids/spheroids that construct the advanced modeling with evolved structural complexity, which propels drug discovery by exhibiting more human specific and diverse pathologies that are not perceived in 2D or animal models. We will then focus on various central nerve system (CNS) disease modeling using human iPSCs, leading to uncovering disease pathogenesis that guides the development of therapeutic strategies. Finally, we will address new opportunities of iPSC-assisted drug discovery with multi-disciplinary approaches from bioengineering to Omics technology. Despite technological challenges, iPSC-derived cytoarchitectures through interactions of diverse cell types mimic patients’ CNS and serve as a platform for therapeutic development and personalized precision medicine.

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