Four secretory proteins synthesized by hepatocytes are transported from endoplasmic reticulum to Golgi complex at different rates.

1984 ◽  
Vol 3 (1) ◽  
pp. 147-152 ◽  
Author(s):  
E. Fries ◽  
L. Gustafsson ◽  
P.A. Peterson
Keyword(s):  
Endoplasmic Reticulum ◽  
Golgi Complex ◽  
Secretory Proteins

scholarly journals PROTEIN SYNTHESIS, STORAGE, AND DISCHARGE IN THE PANCREATIC EXOCRINE CELL

1964 ◽  
Vol 20 (3) ◽  
pp. 473-495 ◽  
Author(s):  
Lucien G. Caro ◽  
George E. Palade
Keyword(s):  
Endoplasmic Reticulum ◽  
Golgi Complex ◽  
Intracellular Transport ◽  
Secretory Proteins ◽  
Zymogen Granules ◽  
Intravenous Injections ◽  
Pancreatic Exocrine ◽  
Exocrine Cell ◽  
Secretory Products ◽  
Electron Microscopical

The synthesis, intracellular transport, storage, and discharge of secretory proteins in and from the pancreatic exocrine cell of the guinea pig were studied by light- and electron microscopical autoradiography using DL-leucine-4,5-H3 as label. Control experiments were carried out to determine: (a) the length of the label pulse in the blood and tissue after intravenous injections of leucine-H3; (b) the amount and nature of label lost during tissue fixation, dehydration, and embedding. The results indicate that leucine-H3 can be used as a label for newly synthesized secretory proteins and as a tracer for their intracellular movements. The autoradiographic observations show that, at ∼5 minutes after injection, the label is localized mostly in cell regions occupied by rough surfaced elements of the endoplasmic reticulum; at ∼20 minutes, it appears in elements of the Golgi complex; and after 1 hour, in zymogen granules. The evidence conclusively shows that the zymogen granules are formed in the Golgi region by a progressive concentration of secretory products within large condensing vacuoles. The findings are compatible with an early transfer of label from the rough surfaced endoplasmic reticulum to the Golgi complex, and suggest the existence of two distinct steps in the transit of secretory proteins through the latter. The first is connected with small, smooth surfaced vesicles situated at the periphery of the complex, and the second with centrally located condensing vacuoles.

Potassium depletion inhibits the intracellular transport of secretory proteins between the endoplasmic reticulum and the Golgi complex

1989 ◽  
Vol 92 (2) ◽  
pp. 173-185
Author(s):  
J.D. Judah ◽  
K.E. Howell ◽  
J.A. Taylor ◽  
P.S. Quinn
Keyword(s):  
Endoplasmic Reticulum ◽  
Golgi Complex ◽  
Intracellular Transport ◽  
Secretory Pathway ◽  
Subcellular Fractionation ◽  
Secretory Proteins ◽  
Mature Form ◽  
Processing Enzymes ◽  
Microscopic Studies ◽  
K Depletion

In this paper we show that hepatocytes that have been depleted of K+ secrete albumin, alpha-1-anti-trypsin and transferrin at a slower rate than cells to which K+ has been returned. K+ depletion has no effect on the intracellular nucleotide pools, and we provide evidence that the inhibitions of secretion caused by depletion of K+ and depletion of ATP are independent. Studies of the processing of alpha-1-anti-trypsin show that K+ depletion inhibits the formation of the mature form of the protein, but that immature forms are never secreted. In cells to which K+ was returned, secretion of the mature form was restored. This implies that transport is blocked at a point before the proteins reach the processing enzymes. Proteins delayed by K+ depletion are not removed from the secretory pathway, but are free to mix with protein synthesized subsequently. These data are supported by subcellular fractionation experiments, which show that the secretory proteins are delayed before reaching the Golgi complex, and by immunoelectron microscopic studies. These show that in K+-deficient cells the morphology of both the endoplasmic reticulum and the Golgi complex is normal. The secretory proteins are trapped in smooth vesicles that contain reaction product when incubated for glucose-6-phosphatase, a marker for the endoplasmic reticulum.

scholarly journals The dynamics of engineered resident proteins in the mammalian Golgi complex relies on cisternal maturation

2013 ◽  
Vol 201 (7) ◽  
pp. 1027-1036 ◽  
Author(s):  
Riccardo Rizzo ◽  
Seetharaman Parashuraman ◽  
Peppino Mirabelli ◽  
Claudia Puri ◽  
John Lucocq ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Golgi Complex ◽  
The Other ◽  
Secretory Proteins ◽  
Membrane Biology ◽  
At Will

After leaving the endoplasmic reticulum, secretory proteins traverse several membranous transport compartments before reaching their destinations. How they move through the Golgi complex, a major secretory station composed of stacks of membranous cisternae, is a central yet unsettled issue in membrane biology. Two classes of mechanisms have been proposed. One is based on cargo-laden carriers hopping across stable cisternae and the other on “maturing” cisternae that carry cargo forward while progressing through the stack. A key difference between the two concerns the behavior of Golgi-resident proteins. Under stable cisternae models, Golgi residents remain in the same cisterna, whereas, according to cisternal maturation, Golgi residents recycle from distal to proximal cisternae via retrograde carriers in synchrony with cisternal progression. Here, we have engineered Golgi-resident constructs that can be polymerized at will to prevent their recycling via Golgi carriers. Maturation models predict the progress of such polymerized residents through the stack along with cargo, but stable cisternae models do not. The results support the cisternal maturation mechanism.

scholarly journals Immunocytochemical localization of BiP to the rough endoplasmic reticulum: evidence for protein sorting by selective retention.

1989 ◽  
Vol 37 (12) ◽  
pp. 1817-1823 ◽  
Author(s):  
D G Bole ◽  
R Dowin ◽  
M Doriaux ◽  
J D Jamieson
Keyword(s):  
Endoplasmic Reticulum ◽  
Golgi Complex ◽  
Membrane System ◽  
Myeloma Cell ◽  
Secretory Protein ◽  
Electron Microscopic Level ◽  
Immunoperoxidase Staining ◽  
Secretory Proteins ◽  
Electron Microscopic ◽  
Exocytic Pathway

Immunoglobulin heavy chain binding protein (BiP) (also known as GRP 78) is a protein of the endoplasmic reticulum (ER) which has been shown to be involved in post-translational processing of nascent membrane and secretory proteins. To determine BiP's location in the exocytic pathway, we localized BiP at the electron microscopic level in mouse myeloma cell lines by immunoperoxidase cytochemistry. BiP was found to be present within the cisternal spaces of the RER and nuclear envelope but was not detected in the cisternae of the Golgi complex. BiP reaction product was also found within transitional elements of the RER but was absent from smooth-surfaced vesicles found between the ER and the Golgi complex. Immunoperoxidase staining of BiP was reduced or absent in regions of a smooth ER membrane system in myelomas that contained endogenous murine retrovirus A particles. All compartments of the exocytic pathway, including the virus-containing smooth ER, stained for IgG, a secretory protein. These observations suggest that BiP is selectively retained in the cisternae of the ER and is not free to enter Golgi-directed transport vesicles. These studies suggest that BiP's subcellular localization may occur by selective interaction with component(s) of the ER.

scholarly journals A vesicular intermediate in the transport of hepatoma secretory proteins from the rough endoplasmic reticulum to the Golgi complex.

1987 ◽  
Vol 104 (2) ◽  
pp. 221-230 ◽  
Author(s):  
H F Lodish ◽  
N Kong ◽  
S Hirani ◽  
J Rasmussen
Keyword(s):  
Endoplasmic Reticulum ◽  
Rough Endoplasmic Reticulum ◽  
Golgi Complex ◽  
Supernatant Fraction ◽  
Secretory Proteins ◽  
Golgi Vesicles ◽  
Intermediate Fraction ◽  
Intermediate Compartment ◽  
Alpha 1 Antitrypsin ◽  
Endoglycosidase H

We have identified a vesicle fraction that contains alpha 1-antitrypsin and other human HepG2 hepatoma secretory proteins en route from the rough endoplasmic reticulum (RER) to the cis face of the Golgi complex. [35S]Methionine pulse-labeled cells were chased for various periods of time, and then a postnuclear supernatant fraction was resolved on a shallow sucrose-D2O gradient. This intermediate fraction has a density lighter than RER or Golgi vesicles. Most alpha 1-antitrypsin in this fraction (P1) bears N-linked oligosaccharides of composition similar to that of alpha 1-antitrypsin within the RER; mainly Man8GlcNac2 with lesser amounts of Man7GlcNac2 and Man9GlcNac2; this suggests that the protein has not yet reacted with alpha-mannosidase-I on the cis face of the Golgi complex. This light vesicle species is the first post-ER fraction to be filled by labeled alpha 1-antitrypsin after a short chase, and newly made secretory proteins enter this compartment in proportion to their rate of exit from the RER and their rate of secretion from the cells: alpha 1-antitrypsin and albumin faster than preC3 and alpha 1-antichymotrypsin, faster, in turn, then transferrin. Deoxynojirimycin, a drug that blocks removal of glucose residues from alpha 1-antitrypsin in the RER and blocks its intracellular maturation, also blocks its appearance in this intermediate compartment. Upon further chase of the cells, we detect sequential maturation of alpha 1-antitrypsin to two other intracellular forms: first, P2, a form that has the same gel mobility as P1 but that bears an endoglycosidase H-resistant oligosaccharide and is found in a compartment--probably the medial Golgi complex--of density higher than that of the intermediate that contains P1; and second, the mature sialylated form of alpha 1-antitrypsin.

scholarly journals Immunocytochemical localization of renin in juxtaglomerular cells.

1985 ◽  
Vol 33 (4) ◽  
pp. 323-332 ◽  
Author(s):  
J Lacasse ◽  
M Ballak ◽  
C Mercure ◽  
J Gutkowska ◽  
C Chapeau ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Rough Endoplasmic Reticulum ◽  
Golgi Complex ◽  
Secretory Granules ◽  
Protein A ◽  
Secretory Proteins ◽  
Juxtaglomerular Cells ◽  
Newborn Mice ◽  
Sequence Of Events ◽  
Flocculent Material

The involvement of various organelles in the synthesis, transport, and packaging of renin in the juxtaglomerular cells of newborn mice has been investigated by immunocytochemistry with the protein A-gold technique. Highly specific rabbit antibodies against mouse submandibular renin were used. Mild fixation and embedding in glycol methacrylate allowed enough sensitivity to identify a steep gradient of labeling from rough endoplasmic reticulum to Golgi complex to secretory granules. Routine fixation and embedding in Epon produced labeling differentials that allowed delineation of hitherto ill-defined types of secretory granules and vacuoles. The classical pattern of synthesis, transport, and packaging of secretory proteins involves the rough endoplasmic reticulum and Golgi complex and seems to apply to renin secretion. Immunoreactive renin is packaged as rhomboid crystals at the trans face of the Golgi complex. The limiting membrane of these rhomboids fuses to form coalescing protogranules where the crystals eventually yield their individuality maturing into secretory granules. Vacuoles containing a flocculent material, with or without a dense core, show significant immunocytochemical labeling. These vacuoles are not associated with the Golgi complex but occupy cytoplasmic areas well endowed with rough endoplasmic reticulum. As judged from their morphological features and their immunoreactivity, the vacuoles do not seem to follow the sequence of events typical of protogranules and coalescing protogranules. They possibly represent a parallel pathway of renin synthesis and transport, involving the nuclear envelope and bypassing the Golgi complex.

Organisation in the Structure of the Cytoplasmic Ground Substance

1978 ◽  
Vol 36 (3) ◽  
pp. 627-639
Author(s):  
K.R. Porter
Keyword(s):  
Endoplasmic Reticulum ◽  
Golgi Complex ◽  
Random Distribution ◽  
Ground Substance ◽  
The Matrix ◽  
Cell Processes ◽  
Cytoplasmic Ground Substance

Most types of cells are known from their structure and overall form to possess a characteristic organization. In some instances this is evident in the non-random disposition of organelles and such system subunits as cisternae of the endoplasmic reticulum or the Golgi complex. In others it appears in the distribution and orientation of cytoplasmic fibrils. And in yet others the organization finds expression in the non-random distribution and orientation of microtubules, especially as found in highly anisometric cells and cell processes. The impression is unavoidable that in none of these cases is the organization achieved without the involvement of the cytoplasmic ground substance (CGS) or matrix. This impression is based on the fact that a matrix is present and that in all instances these formed structures, whether membranelimited or filamentous, are suspended in it. In some well-known instances, as in arrays of microtubules which make up axonemes and axostyles, the matrix resolves itself into bridges (and spokes) between the microtubules, bridges which are in some cases very regularly disposed and uniform in size (Mcintosh, 1973; Bloodgood and Miller, 1974; Warner and Satir, 1974).

Ultrastructural Aspects of Golgi Complex Function in Parathyroid Cells of Winter Frogs

1973 ◽  
Vol 31 ◽  
pp. 680-681
Author(s):  
William J. Dougherty
Keyword(s):  
Golgi Complex ◽  
Secretory Granules ◽  
Complex Function ◽  
Secretory Activity ◽  
Secretory Proteins ◽  
Perivascular Spaces ◽  
Pituitary Cells ◽  
Electron Microscopic ◽  
Ca Ions ◽  
Regulation Of Secretion

The regulation of secretion in exocrine and endocrine cells has long been of interest. Electron microscopic and other studies have demonstrated that secretory proteins synthesized on ribosomes are transported by the rough ER to the Golgi complex where they are concentrated into secretory granules. During active secretion, secretory granules fuse with the cell membrane, liberating and discharging their contents into the perivascular spaces. When secretory activity is suppressed in anterior pituitary cells, undischarged secretory granules may be degraded by lysosomes. In the parathyroid gland, evidence indicates that the level of blood Ca ions regulates both the production and release of parathormone. Thus, when serum Ca is low, synthesis and release of parathormone are both stimulated; when serum Ca is elevated, these processes are inhibited.

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