scholarly journals The Role of the Tethering Proteins p115 and GM130 in Transport through the Golgi Apparatus In Vivo

2000 ◽  
Vol 11 (2) ◽  
pp. 635-645 ◽  
Author(s):  
Joachim Seemann ◽  
Eija Jämsä Jokitalo ◽  
Graham Warren
Keyword(s):  
Intracellular Transport ◽  
Microscopic Analysis ◽  
Electron Microscopic ◽  
Golgi Membranes ◽  
Transport Vesicles ◽  
Golgi Region ◽  
Quantitative Immunofluorescence ◽  
Target Membrane ◽  
Mitotic Phosphorylation

Biochemical data have shown that COPI-coated vesicles are tethered to Golgi membranes by a complex of at least three proteins: p115, giantin, and GM130. p115 binds to giantin on the vesicles and to GM130 on the membrane. We now examine the function of this tethering complex in vivo. Microinjection of an N-terminal peptide of GM130 or overexpression of GM130 lacking this N-terminal peptide inhibits the binding of p115 to Golgi membranes. Electron microscopic analysis of single microinjected cells shows that the number of COP-sized transport vesicles in the Golgi region increases substantially, suggesting that transport vesicles continue to bud but are less able to fuse. This was corroborated by quantitative immunofluorescence analysis, which showed that the intracellular transport of the VSV-G protein was significantly inhibited. Together, these data suggest that this tethering complex increases the efficiency with which transport vesicles fuse with their target membrane. They also provide support for a model of mitotic Golgi fragmentation in which the tethering complex is disrupted by mitotic phosphorylation of GM130.

scholarly journals Characteristics of endoplasmic reticulum-derived transport vesicles.

1994 ◽  
Vol 126 (5) ◽  
pp. 1133-1148 ◽  
Author(s):  
M F Rexach ◽  
M Latterich ◽  
R W Schekman
Keyword(s):  
Membrane Proteins ◽  
Protein Transport ◽  
De Novo ◽  
Microscopic Analysis ◽  
Equilibrium Density ◽  
Protein Markers ◽  
Electron Microscopic ◽  
Golgi Membranes ◽  
Transport Vesicles

We have isolated vesicles that mediate protein transport from the ER to Golgi membranes in perforated yeast. These vesicles, which form de novo during in vitro incubations, carry lumenal and membrane proteins that include core-glycosylated pro-alpha-factor, Bet1, Sec22, and Bos1, but not ER-resident Kar2 or Sec61 proteins. Thus, lumenal and membrane proteins in the ER are sorted prior to transport vesicle scission. Inhibition of Ypt1p-function, which prevents newly formed vesicles from docking to cis-Golgi membranes, was used to block transport. Vesicles that accumulate are competent for fusion with cis-Golgi membranes, but not with ER membranes, and thus are functionally committed to vectorial transport. A 900-fold enrichment was developed using differential centrifugation and a series of velocity and equilibrium density gradients. Electron microscopic analysis shows a uniform population of 60 nm vesicles that lack peripheral protein coats. Quantitative Western blot analysis indicates that protein markers of cytosol and cellular membranes are depleted throughout the purification, whereas the synaptobrevin-like Bet1, Sec22, and Bos1 proteins are highly enriched. Uncoated ER-derived transport vesicles (ERV) contain twelve major proteins that associate tightly with the membrane. The ERV proteins may represent abundant cargo and additional targeting molecules.

scholarly journals Effect of caffeine and reduced temperature (20 degrees C) on the organization of the pre-Golgi and the Golgi stack membranes.

1993 ◽  
Vol 120 (6) ◽  
pp. 1321-1335 ◽  
Author(s):  
J Jäntti ◽  
E Kuismanen
Keyword(s):  
Golgi Complex ◽  
Brefeldin A ◽  
Microscopic Analysis ◽  
Electron Microscopic ◽  
Transport Pathways ◽  
Golgi Stack ◽  
Golgi Membranes ◽  
Golgi Region ◽  
Functional Interface ◽  
Reduced Temperature

In the present study we have dissected the transport pathways between the ER and the Golgi complex using a recently introduced (Kuismanen, E., J. Jäntti, V. Mäkiranta, and M. Sariola. 1992. J. Cell Sci. 102:505-513) inhibition of transport by caffeine at 20 degrees C. Recovery of the Golgi complex from brefeldin A (BFA) treatment was inhibited by caffeine at reduced temperature (20 degrees C) suggesting that caffeine inhibits the membrane traffic between the ER and the Golgi complex. Caffeine at 20 degrees C did not inhibit the BFA-induced retrograde movement of the Golgi membranes. Further, incubation of the cells in 10 mM caffeine at 20 degrees C had profound effects on the distribution and the organization of the pre-Golgi and the Golgi stack membranes. Caffeine treatment at 20 degrees C resulted in a selective and reversible translocation of the pre- and cis-Golgi marker protein (p58) to the periphery of the cell. This caffeine-induced effect on the Golgi complex was different from that induced by BFA, since mannosidase II, a Golgi stack marker, remained perinuclearly located and the Golgi stack coat protein, beta-COP, was not detached from Golgi membranes in the presence of 10 mM caffeine at 20 degrees C. Electron microscopic analysis showed that, in the presence of caffeine at 20 degrees C, the morphology of the Golgi stack was altered and accumulation of numerous small vesicles in the Golgi region was observed. The results in the present study suggest that caffeine at reduced temperature (20 degrees C) reveals a functional interface between the pre-Golgi and the Golgi stack.

scholarly journals Inhibition of oocyte growth factors in vivo modulates ovarian folliculogenesis in neonatal and immature mice

Reproduction ◽  
2010 ◽  
Vol 139 (3) ◽  
pp. 587-598 ◽  
Author(s):  
Samu Myllymaa ◽  
Arja Pasternack ◽  
David G Mottershead ◽  
Matti Poutanen ◽  
Minna M Pulkki ◽  
...  
Keyword(s):  
Growth Factors ◽  
Granulosa Cells ◽  
Microscopic Analysis ◽  
Corpora Lutea ◽  
Electron Microscopic ◽  
Oocyte Growth ◽  
Long Term Study ◽  
Ovarian Folliculogenesis

Growth differentiation factor-9 (GDF9) and bone morphogenetic protein-15 (BMP15) are among the key regulators transmitting the signaling between the oocyte and the surrounding granulosa cells. Previously, it has been shown that a recombinant BMP type II receptor ectodomain–Fc fusion protein (BMPR2ecd–Fc) is able to inhibit the actions of GDF9 and BMP15 in vitro. Here, we have produced bioactive BMPR2ecd–Fc, which was injected i.p. into neonatal mice. Early folliculogenesis was first studied by injecting mice five times with various doses of BMPR2ecd–Fc during the postnatal days 4–12. Folliculogenesis was affected dose dependently, as evidenced by a decreased mitogenesis of granulosa cells of the growing follicles. Furthermore, we also noticed a decrease in the number of secondary and tertiary follicles as well as an increase in the oocyte size. Electron microscopic analysis revealed that the ultrastructure of the granulosa cells of the primary follicles was not affected by the BMPR2ecd–Fc treatment. A second study was conducted to investigate whether a longer treatment with 12 injections during postnatal days 4–28 would inhibit folliculogenesis. Similar effects were observed in the two studies on the early follicular developmental stages. However, in the long-term study, later stages of folliculogenesis were not blocked but rather increased numbers of antral follicles, preovulatory follicles, and corpora lutea were found. We conclude that BMPR2ecd–Fc is a potent modulator of ovarian folliculogenesis in vivo, and thus, is a valuable tool for studying the physiology and downstream effects of oocyte-derived growth factors in vivo.

Quantitative Electron-Microscopic Analysis of the in vivo Effects of Tetrahydrocannabinol on Rat Preovulatory Follicles

1987 ◽  
Vol 128 (3) ◽  
pp. 256-263 ◽  
Author(s):  
Lawrence C. Zoller ◽  
Joanne Quealy Buono ◽  
Kenneth Carr ◽  
Elizabeth Ninke ◽  
Kara Vegso
Keyword(s):  
Microscopic Analysis ◽  
Electron Microscopic Analysis ◽  
Electron Microscopic ◽  
Preovulatory Follicles ◽  
In Vivo Effects

Syk expression in endothelial cells and their morphologic defects in embryonic Syk-deficient mice

Blood ◽  
2001 ◽  
Vol 98 (9) ◽  
pp. 2869-2871 ◽  
Author(s):  
Shigeru Yanagi ◽  
Ryoko Inatome ◽  
Junyi Ding ◽  
Hironori Kitaguchi ◽  
Victor L. J. Tybulewicz ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Endothelial Cell ◽  
Cell Function ◽  
Critical Role ◽  
Microscopic Analysis ◽  
Electron Microscopic ◽  
Vascular Integrity ◽  
Endothelial Cell Function ◽  
Deficient Mice

Abstract Mice deficient in the Syk tyrosine kinase showed severe petechiae in utero and died shortly after birth. The mechanism of this bleeding, however, remains unknown. Here it is shown that this bleeding is caused by morphologic defects of Syk-deficient endothelial cells during embryogenesis. Immunoblot and reverse transcriptase–polymerase chain reaction Northern blot analysis indicated that Syk is expressed in several endothelial cell lines. Immunocytochemical analysis also confirmed that Syk is expressed in the normal embryonic endothelial cells and is absent in Syk-deficient mice. Furthermore, electron microscopic analysis of Syk-deficient mice revealed an abnormal morphogenesis and a decreased number of endothelial cells. The results indicate a critical role for Syk in endothelial cell function and in maintaining vascular integrity in vivo.

Chronic excessive erythrocytosis induces endothelial activation and damage in mouse brain

2006 ◽  
Vol 290 (3) ◽  
pp. R678-R684 ◽  
Author(s):  
O. O. Ogunshola ◽  
V. Djonov ◽  
R. Staudt ◽  
J. Vogel ◽  
M. Gassmann
Keyword(s):  
Endothelial Cells ◽  
Vascular Permeability ◽  
Morphological Characteristics ◽  
Microscopic Analysis ◽  
Endothelial Activation ◽  
Endothelial Damage ◽  
Intercellular Adhesion Molecule ◽  
Intercellular Adhesion Molecule 1 ◽  
Electron Microscopic

Excessive erythrocytosis results in severely increased blood viscosity, which may have significant detrimental effects on endothelial cells and, ultimately, function of the vascular endothelium. Because blood-brain barrier stability is crucial for normal physiological function, we used our previously characterized erythropoietin-overexpressing transgenic (tg6) mouse line (which has a hematocrit of 0.8–0.9) to investigate the effect of excessive erythrocytosis on vessel number, structure, and integrity in vivo. These mice have abnormally high levels of nitric oxide (NO), a potent proinflammatory molecule, suggesting altered vascular permeability and function. In this study, we observed that brain vessel density of tg6 mice was significantly reduced (16%) and vessel diameter was significantly increased (15%) compared with wild-type mice. Although no significant increases in vascular permeability under normoxic or acute hypoxic conditions (8% O2for 4 h) were detected, electron-microscopic analysis revealed altered morphological characteristics of the tg6 endothelium. Tg6 brain vascular endothelial cells appeared to be activated, with increased luminal protrusions reminiscent of ongoing inflammatory processes. Consistent with this observation, we detected increased levels of intercellular adhesion molecule-1 and von Willebrand factor, markers of endothelial activation and damage, in brain tissue. We propose that chronic excessive erythrocytosis and sustained high hematocrit cause endothelial damage, which may, ultimately, increase susceptibility to vascular disease.

scholarly journals ATR is essential for preservation of cell mechanics and nuclear integrity during interstitial migration

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Gururaj Rao Kidiyoor ◽  
Qingsen Li ◽  
Giulia Bastianello ◽  
Christopher Bruhn ◽  
Irene Giovannetti ◽  
...  
Keyword(s):  
Nuclear Envelope ◽  
Mechanical Stress ◽  
Cell Mechanics ◽  
Microscopic Analysis ◽  
Biological Processes ◽  
Electron Microscopic ◽  
In Vivo Models ◽  
Mechanical Coupling ◽  
Damage Response

Abstract ATR responds to mechanical stress at the nuclear envelope and mediates envelope-associated repair of aberrant topological DNA states. By combining microscopy, electron microscopic analysis, biophysical and in vivo models, we report that ATR-defective cells exhibit altered nuclear plasticity and YAP delocalization. When subjected to mechanical stress or undergoing interstitial migration, ATR-defective nuclei collapse accumulating nuclear envelope ruptures and perinuclear cGAS, which indicate loss of nuclear envelope integrity, and aberrant perinuclear chromatin status. ATR-defective cells also are defective in neuronal migration during development and in metastatic dissemination from circulating tumor cells. Our findings indicate that ATR ensures mechanical coupling of the cytoskeleton to the nuclear envelope and accompanying regulation of envelope-chromosome association. Thus the repertoire of ATR-regulated biological processes extends well beyond its canonical role in triggering biochemical implementation of the DNA damage response.

scholarly journals Disruption of muscle architecture and myocardial degeneration in mice lacking desmin.

1996 ◽  
Vol 134 (5) ◽  
pp. 1255-1270 ◽  
Author(s):  
D J Milner ◽  
G Weitzer ◽  
D Tran ◽  
A Bradley ◽  
Y Capetanaki
Keyword(s):  
Smooth Muscle ◽  
Striated Muscle ◽  
Single Gene ◽  
Microscopic Analysis ◽  
Muscle Architecture ◽  
Multisystem Disorder ◽  
Electron Microscopic ◽  
Muscle Tissues ◽  
Extensive Calcification

Desmin, the muscle specific intermediate filament (IF) protein encoded by a single gene, is expressed in all muscle tissues. In mature striated muscle, desmin IFs surround the Z-discs, interlink them together and integrate the contractile apparatus with the sarcolemma and the nucleus. To investigate the function of desmin in all three muscle types in vivo, we generated desmin null mice through homologous recombination. Surprisingly, desmin null mice are viable and fertile. However, these mice demonstrated a multisystem disorder involving cardiac, skeletal, and smooth muscle. Histological and electron microscopic analysis in both heart and skeletal muscle tissues revealed severe disruption of muscle architecture and degeneration. Structural abnormalities included loss of lateral alignment of myofibrils and abnormal mitochondrial organization. The consequences of these abnormalities were most severe in the heart, which exhibited progressive degeneration and necrosis of the myocardium accompanied by extensive calcification. Abnormalities of smooth muscle included hypoplasia and degeneration. The present data demonstrate the essential role of desmin in the maintenance of myofibril, myofiber, and whole muscle tissue structural and functional integrity, and show that the absence of desmin leads to muscle degeneration.

scholarly journals Cell cycle regulation of tubulin RNA level, tubulin protein synthesis, and assembly of microtubules in Physarum.

1984 ◽  
Vol 99 (1) ◽  
pp. 155-165 ◽  
Author(s):  
T Schedl ◽  
T G Burland ◽  
K Gull ◽  
W F Dove
Keyword(s):  
Cell Cycle ◽  
Mitotic Spindle ◽  
Microscopic Analysis ◽  
Nucleic Acid Hybridization ◽  
Electron Microscopic ◽  
Two Dimensional Gel Electrophoresis ◽  
Spindle Microtubules ◽  
Beta 2

The temporal relationship between tubulin expression and the assembly of the mitotic spindle microtubules has been investigated during the naturally synchronous cell cycle of the Physarum plasmodium. The cell cycle behavior of the tubulin isoforms was examined by two-dimensional gel electrophoresis of proteins labeled in vivo and by translation of RNA in vitro. alpha 1-, alpha 2-, beta 1-, and beta 2-tubulin synthesis increases coordinately until metaphase, and then falls, with beta 2 falling more rapidly than beta 1. Nucleic acid hybridization demonstrated that alpha- and beta-tubulin RNAs accumulate coordinately during G2, peaking at metaphase. Quantitative analysis demonstrated that alpha-tubulin RNA increases with apparent exponential kinetics, peaking with an increase over the basal level of greater than 40-fold. After metaphase, tubulin RNA levels fall exponentially, with a short half-life (19 min). Electron microscopic analysis of the plasmodium showed that the accumulation of tubulin RNA begins long before the polymerization of mitotic spindle microtubules. By contrast, the decay of tubulin RNA after metaphase coincides with the depolymerization of the spindle microtubules.

Sign in / Sign up

Export Citation Format

Share Document