scholarly journals Electron cryotomographic view of the deep-sea methane oxidizing bacterium Methyloprofundus sedimenti during active growth. The cell interior contains abundant intracytoplasmic membranes and storage granules. In response to methane starvation cells display

2017 ◽  
Vol 103 (2) ◽  
pp. i-i
Keyword(s):  
Deep Sea ◽  
Cell Interior ◽  
Active Growth ◽  
Intracytoplasmic Membranes ◽  
Storage Granules ◽  
And Storage

scholarly journals Transport and storage of serotonin by thrombin-treated platelets.

1975 ◽  
Vol 65 (2) ◽  
pp. 359-372 ◽  
Author(s):  
H J Reimers ◽  
D J Allen ◽  
I A Feuerstein ◽  
J F Mustard
Keyword(s):  
Storage Capacity ◽  
Platelet Membrane ◽  
Transport Rate ◽  
Primary Reason ◽  
High Concentration ◽  
Serotonin Content ◽  
Amine Storage ◽  
Storage Granules ◽  
And Storage ◽  
Amine Storage Granules

Repeated thrombin treatment of washed platelets prepared from rabbits can decrease the serotonin content of the platelets by about 80%. When these platelets are deaggregated they reaccumulate serotonin but their storage capacity for serotonin is reduced by about 60%. If thrombin-pretreated platelets are allowed to equilibrate with a high concentration of serotonin (123 mu M), they release a smaller percentage of their total serotonin upon further thrombin treatment, in comparison with the percentage of serotonin released from control platelets equilibrated with the same concentration of serotonin calculations indicate that in thrombin-treated platelets reequilibrated with serotonin, two-thirds of the serotonin is in the granule compartment and one-third is in the extragranular compartment, presumably the cytoplasm. Analysis of the exchange of serotonin between the suspending fluid and the platelets showed that thrombin treatment does not alter the transport rate of serotonin across the platelet membrane and does not cause increased diffusion of serotonin from the platelets into the suspending fluid. The primary reason for the reduced serotonin accumulation by the thrombin-treated platelets appears to be loss of amine storage granules or of the storage capacity within the granules.

scholarly journals RADIOAUTOGRAPHIC ANALYSIS OF THE SECRETORY PROCESS IN THE PAROTID ACINAR CELL OF THE RABBIT

1972 ◽  
Vol 53 (2) ◽  
pp. 290-311 ◽  
Author(s):  
J. David Castle ◽  
James D. Jamieson ◽  
George E. Palade
Keyword(s):  
Intracellular Transport ◽  
Secretory Granules ◽  
Close Association ◽  
Low Frequency ◽  
Secretory Process ◽  
Secretory Proteins ◽  
Surgical Removal ◽  
Storage Granules ◽  
And Storage

Intracellular transport of secretory proteins has been studied in the parotid to examine this process in an exocrine gland other than the pancreas and to explore a possible source of less degraded membranes than obtainable from the latter gland. Rabbit parotids were chosen on the basis of size (2–2.5 g per animal), ease of surgical removal, and amylase concentration. Sites of synthesis, rates of intracellular transport, and sites of packaging and storage of newly synthesized secretory proteins were determined radioautographically by using an in vitro system of dissected lobules capable of linear amino acid incorporation for 10 hr with satisfactory preservation of cellular fine structure. Adequate fixation of the tissue with minimal binding of unincorporated labeled amino acids was obtained by using 10% formaldehyde-0.175 M phosphate buffer (pH 7.2) as primary fixative. Pulse labeling with leucine-3H, followed by a chase incubation, showed that the label is initially located (chase: 1–6 min) over the rough endoplasmic reticulum (RER) and subsequently moves as a wave through the Golgi complex (chase: 16–36 min), condensing vacuoles (chase: 36–56 min), immature granules (chase: 56–116 min), and finally mature storage granules (chase: 116–356 min). Distinguishing features of the parotid transport apparatus are: low frequency of RER-Golgi transitional elements, close association of condensing vacuoles with the exit side of Golgi stacks, and recognizable immature secretory granules. Intracelular processing of secretory proteins is similar to that already found in the pancreas, except that the rate is slower and the storage is more prolonged.

The fine structure of "resting bodies" of Bdellovibrio sp. strain W developed in Rhodospirillum rubrum

1972 ◽  
Vol 18 (1) ◽  
pp. 87-92 ◽  
Author(s):  
Judith F. M. Hoeniger ◽  
Rita Ladwig ◽  
Hans Moor
Keyword(s):  
Outer Layer ◽  
Liquid Culture ◽  
Rhodospirillum Rubrum ◽  
Amorphous Material ◽  
Thin Sections ◽  
Host System ◽  
E Coli ◽  
Storage Granules ◽  
And Storage ◽  
Escherichia Coli B

Resting bodies of Bdellovibrio sp. strain W were produced following the infection of Rhodospirillum rubrum in liquid culture. Thin sections showed that young resting bodies possessed a narrow layer of amorphous material at their periphery, and storage granules in the region of the nucleoplasm. In mature resting bodies, the amorphous material (now called the outer layer) had thickened considerably to 30–40 nm, and the cell wall had differentiated into a folded, tripartite inner layer. Freeze-etched preparations of mature resting bodies showed a roughly particulate plasma membrane, a more finely particulate inner layer, and an outer layer having little structure.Bdellovibrio W did not produce resting bodies in a second host, Escherichia coli B. Also B. bacteriovorus strain 109 failed to form resting bodies in E. coli B, its usual host. It also failed to grow in cultures of R. rubrum. These restricted experiments suggest that the development of resting bodies may be specific for the Bdellovibrio W – R. rubrum parasite–host system.

scholarly journals Sorting and Secretion of Salivary Proteins

1993 ◽  
Vol 4 (3) ◽  
pp. 393-398 ◽  
Author(s):  
J. David Castle ◽  
Anna M. Castle
Keyword(s):  
Intracellular Transport ◽  
Salivary Proteins ◽  
Small Subset ◽  
Storage Site ◽  
Secretion Granules ◽  
Storage Granules ◽  
And Storage ◽  
Selective Aggregation ◽  
Self Aggregation ◽  
Proline Rich Protein

Most salivary proteins are stored in secretion granules prior to export from acinar cells in response to neural stimuli. A small subset of these proteins undergo unstimulated secretion without apparent storage. This pathway probably comprises vesicles that bud from maturing storage granules and carries proteins that do not aggregate efficiently at the storage site. Expression of a parotid proline-rich protein (and deletion mutants) in pituitary AtT-20 cells has shown that an N-terminal domain is necessary for storage in secretion granules. Evidence suggests that self-aggregation of proline-rich protein mediated by this domain may function in both efficient intracellular transport and storage. Thus selective aggregation may be an important secretory sorting mechanism.

scholarly journals The mutation N528S in the von Willebrand factor (VWF) propeptide causes defective multimerization and storage of VWF

Blood ◽  
2010 ◽  
Vol 115 (22) ◽  
pp. 4580-4587 ◽  
Author(s):  
Sandra L. Haberichter ◽  
Ulrich Budde ◽  
Tobias Obser ◽  
Sonja Schneppenheim ◽  
Cornelia Wermes ◽  
...  
Keyword(s):  
Von Willebrand Factor ◽  
Mammalian Cells ◽  
Consensus Sequence ◽  
Von Willebrand Disease ◽  
Relative Reduction ◽  
Homozygous Mutation ◽  
Storage Granules ◽  
Von Willebrand ◽  
And Storage ◽  
Willebrand Factor

Abstract We characterized a consanguineous Turkish family suffering from von Willebrand disease (VWD) with significant mucocutaneous and joint bleeding. The relative reduction of large plasma von Willebrand factor (VWF) multimers and the absent VWF triplet structure was consistent with type 2A (phenotype IIC) VWD. Surprisingly, platelet VWF was completely deficient of multimers beyond the VWF protomer, suggesting defective α-granular storage of larger multimers. Patients were nearly unresponsive to desmopressin acetate, consistent with a lack of regulated VWF release from endothelial cell Weibel-Palade bodies, suggesting defective storage also in endothelial cells. We identified an N528S homozygous mutation in the VWF propeptide D2 domain, predicting the introduction of an additional N-glycosylation site at amino acid 526 in close vicinity to a “CGLC” disulphide isomerase consensus sequence. Expression studies in mammalian cells demonstrated that N528S-VWF was neither normally multimerized nor trafficked to storage granules. However, propeptide containing the N528S mutation trafficked normally to storage granules. Our data indicate that the patients' phenotype is the result of defective multimerization, storage, and secretion. In addition, we have identified a potentially novel pathogenic mechanism of VWD, namely a transportation and storage defect of mature VWF due to defective interaction with its transporter, the mutant propeptide.

scholarly journals Cysteine proteinases in rat parathyroid cells with special reference to their correlation with parathyroid hormone (PTH) in storage granules.

1993 ◽  
Vol 41 (2) ◽  
pp. 273-282 ◽  
Author(s):  
Y Hashizume ◽  
S Waguri ◽  
T Watanabe ◽  
E Kominami ◽  
Y Uchiyama
Keyword(s):  
Electron Microscopy ◽  
Parathyroid Hormone ◽  
Special Reference ◽  
Secretory Granules ◽  
Cysteine Proteinases ◽  
Double Immunostaining ◽  
Thin Sections ◽  
Storage Granules ◽  
Golgi Network ◽  
And Storage

To further understand the roles of storage granules in parathyroid cells, we examined by immunocytochemistry the localization of cathepsins B and H and of PTH in rat parathyroid gland. In semi-thin sections, small and large granular immunodeposits for cathepsins B and H appeared in the cells, whereas those for PTH were detected throughout the cells, especially in perinuclear regions. By electron microscopy, immunogold particles indicating cathepsins B and H labeled lysosomes and storage granules, whereas those showing PTH were localized in storage granules, small secretory granules, and the trans-Golgi network. Small vesicles labeled by immunogold particles showing these proteinases often appeared close to the storage granules. By double immunostaining, immunogold particles indicating these proteinases were co-localized with those for PTH in storage granules. By EDTA treatment, immunoreactivity for cathepsins B and H and for PTH was notably reduced in the cells, but immunoreactivity for the proteinases was still seen in lysosomes. These results suggest that storage granules in the rat parathyroid cells fuse with small vesicles containing cathepsins B and H, which may participate in regulating the intracellular PTH levels by degrading PTH in the granules.

scholarly journals Differential trafficking of soluble and integral membrane secretory granule-associated proteins

1994 ◽  
Vol 124 (1) ◽  
pp. 33-41 ◽  
Author(s):  
SL Milgram ◽  
BA Eipper ◽  
RE Mains
Keyword(s):  
Cell Surface ◽  
Secretory Granule ◽  
Secretory Pathway ◽  
Secretory Granules ◽  
Posttranslational Processing ◽  
Endoproteolytic Cleavage ◽  
Associated Proteins ◽  
Storage Granules ◽  
Regulated Secretory Pathway ◽  
And Storage

The posttranslational processing enzyme peptidylglycine alpha-amidating monooxygenase (PAM) occurs naturally in integral membrane and soluble forms. With the goal of understanding the targeting of these proteins to secretory granules, we have compared the maturation, processing, secretion, and storage of PAM proteins in stably transfected AtT-20 cells. Integral membrane and soluble PAM proteins exit the ER and reach the Golgi apparatus with similar kinetics. Biosynthetic labeling experiments demonstrated that soluble PAM proteins were endoproteolytically processed to a greater extent than integral membrane PAM; this processing occurred in the regulated secretory pathway and was blocked by incubation of cells at 20 degrees C. 16 h after a biosynthetic pulse, a larger proportion of soluble PAM proteins remained cell-associated compared with integral membrane PAM, suggesting that soluble PAM proteins were more efficiently targeted to storage granules. The nonstimulated secretion of soluble PAM proteins peaked 1-2 h after a biosynthetic pulse, suggesting that release was from vesicles which bud from immature granules during the maturation process. In contrast, soluble PAM proteins derived through endoproteolytic cleavage of integral membrane PAM were secreted in highest amount during later times of chase. Furthermore, immunoprecipitation of cell surface-associated integral membrane PAM demonstrated that very little integral membrane PAM reached the cell surface during early times of chase. However, when a truncated PAM protein lacking the cytoplasmic tail was expressed in AtT-20 cells, > 50% of the truncated PAM-1 protein reached the cell surface within 3 h. We conclude that the trafficking of integral membrane and soluble secretory granule-associated enzymes differs, and that integral membrane PAM proteins are less efficiently retained in maturing secretory granules.

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