Secretory Membranes and the Exocrine Storage Compartment

2011 ◽  
Author(s):  
Richard S. Cameron ◽  
Peter Arvan ◽  
J. David Castle
Keyword(s):  
Storage Compartment

Studies of Vitamin B12 Metabolism in Patients with Chronic Hepatitis and Liver Cirrhosis

1968 ◽  
Vol 07 (04) ◽  
pp. 371-387
Author(s):  
T. Spârchez ◽  
B. Gheorghescu ◽  
Gh. Jovin ◽  
Elena Merculiev
Keyword(s):  
Liver Cirrhosis ◽  
Chronic Hepatitis ◽  
Vitamin B12 ◽  
Tracer Technique ◽  
Storage Compartment ◽  
And Storage

SummaryWe have studied the kinetiks of vitamin B12 and especially the liver compartment, in 28 normals and 76 patients with chronic hepatitis and liver cirrhosis.The study was carried out by means of vitamin B12 58Co, administered per os (alone or followed by “flushing dosis”), vitamin B12 57Co administered intravenously and by double tracer technique.Our results indicate the Pertubation of intrahepatic storage compartment of radiocobalamine, in patients with chronic hepatitis and especially in patients with active hepatitis and in cirrhotics.This deficiency can be explained probably, by an alteration of the transport to the liver of the absorbed vitamin B12, by an inadequate chemical forme, by hepatic enzymatic disturbances or by excessive handling and storage in extrahepatic compartment.

The sea urchin egg yolk granule is a storage compartment for HCL-32, an extracellular matrix protein

1998 ◽  
Vol 76 (1) ◽  
pp. 83-88 ◽  
Author(s):  
Janice Mayne ◽  
John J Robinson
Keyword(s):  
Extracellular Matrix ◽  
Sea Urchin ◽  
Blot Analysis ◽  
Extracellular Matrix Protein ◽  
Yolk Granule ◽  
Cortical Granules ◽  
Yolk Granules ◽  
Storage Compartment ◽  
Protein Gel ◽  
Stage Of Development

We have utilized protein gel blot analysis and immunogold labelling to define the intracellular storage compartment for HCL-32, a 32-kDa protein component of the sea urchin embryonic extracellular matrices, the hyaline layer and basal lamina. Anti-HCL-32 antiserum specifically labelled yolk granules in unfertilized eggs. Cortical granules, mitochondria, sparse granules, and lipid vacuoles were not labelled. Label continued to be detected in the yolk granules through to the blastula stage of development. However, by the gastrula stage no labelling was detected in the yolk granules. In protein gel blot analysis HCL-32 was detected in yolk granules prepared from unfertilized eggs. These results clearly define the yolk granule as a storage compartment for HCL-32, an extracellular matrix protein.Key words: embryo, yolk granule, extracellular matrix.

scholarly journals Compartmentation of uracil in Euglena gracilis.

1983 ◽  
Vol 3 (4) ◽  
pp. 613-622 ◽  
Author(s):  
C H Wasternack
Keyword(s):  
Environmental Conditions ◽  
Euglena Gracilis ◽  
Rna Synthesis ◽  
Storage Compartment ◽  
Active Pool ◽  
Tracer Kinetic ◽  
Cell Strains ◽  
Metabolic Pool ◽  
Lag Times

Compartmentation of uracil in the flagellate Euglena gracilis was studied by tracer-kinetic experiments. Lag times in the equilibration of exogenously given and intracellularly present uracil before linear labeling of catabolic and anabolic products was determined to estimate the size of its metabolically active pool. This pool operates in the incorporation and degradation of uracil. There were the same lag times in forming both final products when measured in parallel and when measured after preloading with pyrimidines, in different cell strains, and under various environmental conditions. The amount of the metabolically active uracil pool, estimated as 11 pmol/10(7) heterotrophically growing cells, decreased to almost zero during light-induced RNA synthesis and could be changed by preloading with uracil or thymine. Besides this metabolic pool, cells may contain large amounts of uracil in a membrane-enclosed storage compartment (up to 12 nmol/10(7) cells). This is metabolically inert, but may be mobilized by nitrogen-carbon starvation. The role of uracil compartmentation in this metabolically flexible organism is discussed.

scholarly journals The Glucose Transporter 4 FQQI Motif Is Necessary for Akt Substrate of 160-Kilodalton-Dependent Plasma Membrane Translocation But Not Golgi-Localized γ-Ear-Containing Arf-Binding Protein-Dependent Entry into the Insulin-Responsive Storage Compartment

2007 ◽  
Vol 21 (12) ◽  
pp. 3087-3099 ◽  
Author(s):  
Encarnación Capilla ◽  
Naoko Suzuki ◽  
Jeffrey E. Pessin ◽  
June Chunqiu Hou
Keyword(s):  
Plasma Membrane ◽  
Point Mutation ◽  
Glucose Transporter ◽  
Binding Protein ◽  
Amino Terminus ◽  
Glucose Transporter 4 ◽  
Wild Type ◽  
Intracellular Loop ◽  
Storage Compartment ◽  
Intracellular Sequestration

Abstract Newly synthesized glucose transporter 4 (GLUT4) enters into the insulin-responsive storage compartment in a process that is Golgi-localized γ-ear-containing Arf-binding protein (GGA) dependent, whereas insulin-stimulated translocation is regulated by Akt substrate of 160 kDa (AS160). In the present study, using a variety of GLUT4/GLUT1 chimeras, we have analyzed the specific motifs of GLUT4 that are important for GGA and AS160 regulation of GLUT4 trafficking. Substitution of the amino terminus and the large intracellular loop of GLUT4 into GLUT1 (chimera 1-441) fully recapitulated the basal state retention, insulin-stimulated translocation, and GGA and AS160 sensitivity of wild-type GLUT4 (GLUT4-WT). GLUT4 point mutation (GLUT4-F5A) resulted in loss of GLUT4 intracellular retention in the basal state when coexpressed with both wild-type GGA and AS160. Nevertheless, similar to GLUT4-WT, the insulin-stimulated plasma membrane localization of GLUT4-F5A was significantly inhibited by coexpression of dominant-interfering GGA. In addition, coexpression with a dominant-interfering AS160 (AS160-4P) abolished insulin-stimulated GLUT4-WT but not GLUT4-F5A translocation. GLUT4 endocytosis and intracellular sequestration also required both the amino terminus and large cytoplasmic loop of GLUT4. Furthermore, both the FQQI and the SLL motifs participate in the initial endocytosis from the plasma membrane; however, once internalized, unlike the FQQI motif, the SLL motif is not responsible for intracellular recycling of GLUT4 back to the specialized compartment. Together, we have demonstrated that the FQQI motif within the amino terminus of GLUT4 is essential for GLUT4 endocytosis and AS160-dependent intracellular retention but not for the GGA-dependent sorting of GLUT4 into the insulin-responsive storage compartment.

scholarly journals Regulated resurfacing of a somatostatin receptor storage compartment fine-tunes pituitary secretion

2019 ◽  
Vol 219 (1) ◽  
Author(s):  
Walaa Alshafie ◽  
Vincent Francis ◽  
Klaudia Bednarz ◽  
Yingzhou Edward Pan ◽  
Thomas Stroh ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Glucose Transporter ◽  
Somatostatin Receptor ◽  
Receptor Activation ◽  
Receptor Subtype ◽  
Pituitary Hormone ◽  
Pituitary Cells ◽  
Hormone Release ◽  
Serum Growth Hormone ◽  
Storage Compartment

The surfacing of the glucose transporter GLUT4 driven by insulin receptor activation provides the prototypic example of a homeostasis response dependent on mobilization of an intracellular storage compartment. Here, we generalize this concept to a G protein–coupled receptor, somatostatin receptor subtype 2 (SSTR2), in pituitary cells. Following internalization in corticotropes, SSTR2 moves to a juxtanuclear syntaxin-6–positive compartment, where it remains until the corticotropes are stimulated with corticotropin releasing factor (CRF), whereupon SSTR2 exits the compartment on syntaxin-6–positive vesicular/tubular carriers that depend on Rab10 for their fusion with the plasma membrane. As SSTR2 activation antagonizes CRF-mediated hormone release, this storage/resurfacing mechanism may allow for a physiological homeostatic feedback system. In fact, we find that SSTR2 moves from an intracellular compartment to the cell surface in pituitary gland somatotropes, concomitant with increasing levels of serum growth hormone (GH) during natural GH cycles. Our data thus provide a mechanism by which signaling-mediated plasma membrane resurfacing of SSTR2 can fine-tune pituitary hormone release.

Defence by plant toxins in milkweed bugs (Heteroptera: Lygaeinae) through the evolution of a sophisticated storage compartment

2016 ◽  
Vol 42 (1) ◽  
pp. 15-30 ◽  
Author(s):  
CHRISTIANE BRAMER ◽  
FRANK FRIEDRICH ◽  
SUSANNE DOBLER
Keyword(s):  
Plant Toxins ◽  
Storage Compartment

Compartmentation of uracil in Euglena gracilis

1983 ◽  
Vol 3 (4) ◽  
pp. 613-622
Author(s):  
C H Wasternack
Keyword(s):  
Environmental Conditions ◽  
Euglena Gracilis ◽  
Rna Synthesis ◽  
Storage Compartment ◽  
Active Pool ◽  
Tracer Kinetic ◽  
Cell Strains ◽  
Metabolic Pool ◽  
Lag Times

Compartmentation of uracil in the flagellate Euglena gracilis was studied by tracer-kinetic experiments. Lag times in the equilibration of exogenously given and intracellularly present uracil before linear labeling of catabolic and anabolic products was determined to estimate the size of its metabolically active pool. This pool operates in the incorporation and degradation of uracil. There were the same lag times in forming both final products when measured in parallel and when measured after preloading with pyrimidines, in different cell strains, and under various environmental conditions. The amount of the metabolically active uracil pool, estimated as 11 pmol/10(7) heterotrophically growing cells, decreased to almost zero during light-induced RNA synthesis and could be changed by preloading with uracil or thymine. Besides this metabolic pool, cells may contain large amounts of uracil in a membrane-enclosed storage compartment (up to 12 nmol/10(7) cells). This is metabolically inert, but may be mobilized by nitrogen-carbon starvation. The role of uracil compartmentation in this metabolically flexible organism is discussed.

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