scholarly journals Cell Secretion: Current Structural and Biochemical Insights

2010 ◽  
Vol 10 ◽  
pp. 2054-2069 ◽  
Author(s):  
Saurabh Trikha ◽  
Elizabeth C. Lee ◽  
Aleksandar M. Jeremic
Keyword(s):  
Plasma Membrane ◽  
Secretory Vesicles ◽  
Intercellular Signaling ◽  
Cell Secretion ◽  
Membrane Structures ◽  
Calcium Dependent ◽  
Cell Plasma ◽  
Membrane Bound ◽  
And Control ◽  
Fusion Pores

Essential physiological functions in eukaryotic cells, such as release of hormones and digestive enzymes, neurotransmission, and intercellular signaling, are all achieved by cell secretion. In regulated (calcium-dependent) secretion, membrane-bound secretory vesicles dock and transiently fuse with specialized, permanent, plasma membrane structures, called porosomes or fusion pores. Porosomes are supramolecular, cup-shaped lipoprotein structures at the cell plasma membrane that mediate and control the release of vesicle cargo to the outside of the cell. The sizes of porosomes range from 150nm in diameter in acinar cells of the exocrine pancreas to 12nm in neurons. In recent years, significant progress has been made in our understanding of the porosome and the cellular activities required for cell secretion, such as membrane fusion and swelling of secretory vesicles. The discovery of the porosome complex and the molecular mechanism of cell secretion are summarized in this article.

scholarly journals vH+-ATPase-induced intracellular acidification is critical to glucose-stimulated insulin secretion

2019 ◽  
Author(s):  
Akshata R. Naik ◽  
Brent J. Formosa ◽  
Rishika G. Pulvender ◽  
Asiri G. Liyanaarachchi ◽  
Bhanu P. Jena
Keyword(s):  
Plasma Membrane ◽  
Insulin Secretion ◽  
Secretory Vesicles ◽  
Intracellular Acidification ◽  
Cell Secretion ◽  
Atpase Inhibitor ◽  
Cell Plasma Membrane ◽  
Min6 Cells ◽  
Cell Plasma ◽  
Glucose Stimulated Insulin Secretion

ABSTRACTSwelling of secretory vesicles is critical for the regulated expulsion of intra-vesicular contents from cells during secretion. At the secretory vesicle membrane of the exocrine pancreas and neurons, GTP-binding G proteins, vH+-ATPase, potassium channels and AQP water channels, are among the players implicated in vesicle volume regulation. Here we report in insulin secreting MIN6 cells, the requirement of vH+-ATPase-mediated intracellular acidification, on glucose-stimulated insulin release. MIN6 cells exposed to the vH+-ATPase inhibitor Bafilomycin A show decreased acidification of the cytosolic compartment that include insulin-carrying granules. Additionally, a loss of insulin granule association with the cell plasma membrane is demonstrated and results in a decrease in glucose-stimulated insulin secretion and accumulation of intracellular insulin. These results suggest that vH+-ATPase-mediated intracellular acidification is required both at the level of secretory vesicles and the cell plasma membrane for cell secretion.

Functional Organization of the Porosome Complex and Associated Structures Facilitating Cellular Secretion

Physiology ◽  
2009 ◽  
Vol 24 (6) ◽  
pp. 367-376 ◽  
Author(s):  
Bhanu P. Jena
Keyword(s):  
Plasma Membrane ◽  
Functional Organization ◽  
Secretory Activity ◽  
Human Platelets ◽  
Frog Neuromuscular Junction ◽  
Cell Secretion ◽  
Cell Plasma Membrane ◽  
Cell Plasma ◽  
Membrane Bound ◽  
Cellular Secretion

Porosomes, the universal secretory machinery at the cell plasma membrane, are cup-shaped supramolecular lipoprotein structures, where membrane-bound vesicles transiently dock and fuse to release intravesicular contents during cell secretion. In this review, the discovery of the porosome and its structure, dynamics, composition, and functional reconstitution are outlined. Furthermore, the architecture of porosome-like structures such as the “canaliculi system” in human platelets and various associated structures such as the T-bars at the Drosophila synapse or the “beams,” “ribs,” and “pegs” at the frog neuromuscular junction, each organized to facilitate a certain specialized secretory activity, are briefly discussed.

scholarly journals Programmed ER fragmentation drives selective ER inheritance and degradation in budding yeast meiosis

2021 ◽  
Author(s):  
George M. Otto ◽  
Tia Cheunkarndee ◽  
Jessica M. Leslie ◽  
Gloria A. Brar
Keyword(s):  
Plasma Membrane ◽  
Cell Differentiation ◽  
Budding Yeast ◽  
Developmentally Regulated ◽  
Selective Degradation ◽  
Cell Plasma ◽  
Membrane Tethering ◽  
Membrane Bound ◽  
Yeast Meiosis ◽  
And Function

AbstractThe endoplasmic reticulum (ER) is a membrane-bound organelle with diverse, essential functions that rely on the maintenance of membrane shape and distribution within cells. ER structure and function are remodeled in response to changes in cellular demand, such as the presence of external stressors or the onset of cell differentiation, but mechanisms controlling ER remodeling during cell differentiation are not well understood. Here, we describe a series of developmentally regulated changes in ER morphology and composition during budding yeast meiosis, a conserved differentiation program that gives rise to gametes. During meiosis, the cortical ER undergoes fragmentation before collapsing away from the plasma membrane at anaphase II. This programmed collapse depends on the meiotic transcription factor Ndt80, conserved ER membrane structuring proteins Lnp1 and reticulons, and the actin cytoskeleton. A subset of ER is retained at the mother cell plasma membrane and excluded from gamete cells via the action of ER-plasma membrane tethering proteins. ER remodeling is coupled to ER degradation by selective autophagy, which is regulated by the developmentally timed expression of the autophagy receptor Atg40. Autophagy relies on ER collapse, as artificially targeting ER proteins to the cortically retained ER pool prevents their degradation. Thus, developmentally programmed changes in ER morphology determine the selective degradation or inheritance of ER subdomains by gametes.

scholarly journals Fusion pore or porosome: structure and dynamics

2003 ◽  
Vol 176 (2) ◽  
pp. 169-174 ◽  
Author(s):  
BP Jena
Keyword(s):  
Plasma Membrane ◽  
Neuroendocrine Cells ◽  
Fusion Pore ◽  
Secretory Cells ◽  
Force Microscopy ◽  
Membrane Pores ◽  
Atomic Force ◽  
Cell Plasma ◽  
Electrophysiological Measurements ◽  
Membrane Bound

Electrophysiological measurements on live secretory cells almost a decade ago suggested the presence of fusion pores at the cell plasma membrane. Membrane-bound secretory vesicles were hypothesized to dock and fuse at these sites, to release their contents. Our studies using atomic force microscopy on live exocrine and neuroendocrine cells demonstrate the presence of such plasma membrane pores, revealing their morphology and dynamics at near nm resolution and in real time.

scholarly journals The plant calcium-dependent protein kinase CPK3 phosphorylates REM1.3 to restrict viral infection

2017 ◽  
Author(s):  
Artemis Perraki ◽  
Julien Gronnier ◽  
Paul Gouguet ◽  
Marie Boudsocq ◽  
Anne-Flore Deroubaix ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Protein Kinase ◽  
Cell Movement ◽  
Dependent Protein Kinase ◽  
Calcium Dependent ◽  
Intrinsically Disordered ◽  
Dependent Protein ◽  
Membrane Bound ◽  
Calcium Dependent Protein Kinase ◽  
Group 1

AbstractPlants respond to pathogens through dynamic regulation of plasma membrane-bound signaling pathways. To date, how the plant plasma membrane is involved in responses to viruses is mostly unknown. Here, we show that plant cells sense the Potato virus X (PVX) COAT PROTEIN and TRIPLE GENE BLOCK 1 proteins and subsequently trigger the activation of a membrane-bound calcium-dependent kinase. We show that the Arabidopsis thaliana CALCIUM-DEPENDENT PROTEIN KINASE 3-interacts with group 1 REMORINs in vivo, phosphorylates the intrinsically disordered N-terminal domain of the Group 1 REMORIN REM1.3, and restricts PVX cell-to-cell movement. REM1.3-s phospho-status defines its plasma membrane nanodomain organization and is crucial for REM1.3-dependent restriction of PVX cell-to-cell movement by regulation of callose deposition at plasmodesmata. This study unveils plasma membrane nanodomain-associated molecular events underlying the plant immune response to viruses.

scholarly journals Extracellular Vesicles: Exosomes and Microvesicles, Integrators of Homeostasis

Physiology ◽  
2019 ◽  
Vol 34 (3) ◽  
pp. 169-177 ◽  
Author(s):  
Philip D. Stahl ◽  
Graca Raposo
Keyword(s):  
Plasma Membrane ◽  
Extracellular Vesicles ◽  
Intercellular Signaling ◽  
Membrane Structures

Extracellular vesicles (EVs), cell-derived membrane structures, are secreted after fusion of endosomes with the plasma membrane (exosomes) or shed from the plasma membrane (microvesicles). EVs play a key role both in physiological balance and homeostasis and in disease processes by their ability to participate in intercellular signaling and communication.

Localization of five annexins in J774 macrophages and on isolated phagosomes

1997 ◽  
Vol 110 (10) ◽  
pp. 1199-1213 ◽  
Author(s):  
M. Diakonova ◽  
V. Gerke ◽  
J. Ernst ◽  
J.P. Liautard ◽  
G. van der Vusse ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Annexin V ◽  
Dependent Manner ◽  
Calcium Dependent ◽  
Latex Beads ◽  
Early Endosomes ◽  
Membrane Protrusions ◽  
Membrane Bound ◽  
Related Proteins

Annexins are a family of structurally related proteins which bind phospholipids in a calcium-dependent manner. Although the precise functions of annexins are unknown, there is an accumulating set of data arguing for a role for some of them in vesicular transport and, specifically, in membrane-membrane or membrane-cytoskeletal interactions during these processes. Here we describe our qualitative and quantitative analysis of the localization of annexins I-V in J774 macrophages that had internalized latex beads, both with and without IgG opsonization. Our results show that whereas all these annexins are present on both the plasma membrane and on phagosomes, the localization on other organelles differs. Annexins I, II, III and V were detected on early endosomes, while only annexin V was seen on late endocytic organelles and mitochondria. Annexins I and II distributed along the plasma membrane non-uniformly and co-localized with F-actin at the sites of membrane protrusions. We also investigated by western blot analysis the association of annexins with purified phagosomes isolated at different time-points after latex bead internalization. While the amounts of annexins I, II, III and V associated with phagosomes were similar at all times after their formation, the level of annexin IV was significantly higher on older phagosomes. Whereas annexins I, II, IV and V could be removed from phagosome membranes with a Ca2+ chelator they remained membrane bound under low calcium conditions. In contrast, annexin III was removed under these conditions and needed a relatively high Ca2+ concentration to remain phagosome bound. Because of their purity and ease of preparation we suggest that phagosomes are a powerful system to study the potential role of annexins in membrane traffic.

scholarly journals Comparative de novo transcriptome analysis identifies salinity stress responsive genes and metabolic pathways in sugarcane and its wild relative Erianthus arundinaceus [Retzius] Jeswiet

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
P. Vignesh ◽  
C. Mahadevaiah ◽  
R. Parimalan ◽  
R. Valarmathi ◽  
S. Dharshini ◽  
...  
Keyword(s):  
Signal Transduction ◽  
Plasma Membrane ◽  
Transcriptome Analysis ◽  
Metabolic Pathways ◽  
De Novo ◽  
Biological Processes ◽  
Wild Relative ◽  
De Novo Transcriptome ◽  
Membrane Bound ◽  
And Control

AbstractErianthus arundinaceus [Retzius] Jeswiet, a wild relative of sugarcane has a high biomass production potential and a reservoir of many genes for superior agronomic traits and tolerance to biotic and abiotic stresses. A comparative physiological, anatomical and root transcriptome analysis were carried out to identify the salt-responsive genes and metabolic pathways associated with salt-tolerant E. arundinaceus genotype IND99-907 and salinity-sensitive sugarcane genotype Co 97010. IND99-907 recorded growth of young leaves, higher proline content, higher relative water content, intact root anatomical structures and lower Na+/K+, Ca2+/K+ and Mg2+/K+ ratio as compared to the sugarcane genotype Co 97010. We have generated four de novo transcriptome assemblies between stressed and control root samples of IND99-907 and Co 97010. A total of 649 and 501 differentially expressed genes (FDR<0.01) were identified from the stressed and control libraries of IND99-907 and Co 97010 respectively. Genes and pathways related to early stress-responsive signal transduction, hormone signalling, cytoskeleton organization, cellular membrane stabilization, plasma membrane-bound calcium and proton transport, sodium extrusion, secondary metabolite biosynthesis, cellular transporters related to plasma membrane-bound trafficking, nucleobase transporter, clathrin-mediated endocytosis were highly enriched in IND99-907. Whereas in Co 97010, genes related to late stress-responsive signal transduction, electron transport system, senescence, protein degradation and programmed cell death, transport-related genes associated with cellular respiration and mitochondrial respiratory chain, vesicular trafficking, nitrate transporter and fewer secondary metabolite biosynthetic genes were highly enriched. A total of 27 pathways, 24 biological processes, three molecular functions and one cellular component were significantly enriched (FDR≤ 0.05) in IND99-907 as compared to 20 pathways, two biological processes without any significant molecular function and cellular components in Co 97010, indicates the unique and distinct expression pattern of genes and metabolic pathways in both genotypes. The genomic resources developed from this study is useful for sugarcane crop improvement through development of genic SSR markers and genetic engineering approaches.

Analysis of the Anterior Secretory Cells of Onchidohs Muricata (Nudibranchia)

1981 ◽  
Vol 39 ◽  
pp. 614-615
Author(s):  
Roy Skidmore
Keyword(s):  
Endoplasmic Reticulum ◽  
Secretory Granules ◽  
Golgi Body ◽  
The Body ◽  
Secretory Cells ◽  
Secretory Vesicles ◽  
High Magnification ◽  
Large Numbers ◽  
Membrane Bound ◽  
Sole Of The Foot

The long-necked secretory cells in Onchidoris muricata are distributed in the anterior sole of the foot. These cells are interspersed among ciliated columnar and conical cells as well as short-necked secretory gland cells. The long-necked cells contribute a significant amount of mucoid materials to the slime on which the nudibranch travels. The body of these cells is found in the subepidermal tissues. A long process extends across the basal lamina and in between cells of the epidermis to the surface of the foot. The secretory granules travel along the process and their contents are expelled by exocytosis at the foot surface.The contents of the cell body include the nucleus, some endoplasmic reticulum, and an extensive Golgi body with large numbers of secretory vesicles (Fig. 1). The secretory vesicles are membrane bound and contain a fibrillar matrix. At high magnification the similarity of the contents in the Golgi saccules and the secretory vesicles becomes apparent (Fig. 2).

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