Disease relevance of Reticulum

• Localization of the tomato bushy stunt virus replication protein p33 reveals a peroxisome-to-endoplasmic reticulum sorting pathway [1].
• Human anti-endoplasmic reticulum autoantibodies appearing in a drug-induced hepatitis are directed against a human liver cytochrome P-450 that hydroxylates the drug [2].
• Murine leukemia viruses capable of malignant transformation of mink tissue culture cells have been isolated from an AKR thymoma cell line and from a spontaneous reticulum cell sarcoma in an NIH Swiss mouse partially congenic for the AKR ecotropic virus-inducing locus Akv-2 [3].
• Previous studies from our laboratory have demonstrated that particulate glucan is efficacious in the therapy of a syngeneic murine reticulum cell sarcoma (M5706), which specifically metastasizes from its primary site to the liver [4].
• The purpose of this study was to determine whether the activation of inducible nitric oxide synthase (iNOS) can serve as a target for immunotherapeutic agents for treatment of murine reticulum cell sarcoma metastases [5].

High impact information on Reticulum

• Chronic phospholamban-sarcoplasmic reticulum calcium ATPase interaction is the critical calcium cycling defect in dilated cardiomyopathy [6].
• The Golgi apparatus in animal cells comprises a reticulum of linked stacks in the pericentriolar and often in the juxtanuclear regions of the cell [7].
• Protein 4.1 forms a stable ternary complex with spectrin and actin, thereby strengthening the reticulum and anchoring it directly to the lipid bilayer or to another intrinsic protein, glycophorin [8].
• Ca2+ is released from the SR via two types of ionic channels [ryanodine- and inositol 1,4,5-trisphosphate-gated], whereas accumulation from thecytoplasm occurs exclusively by an energy-dependent sarco-endoplasmic reticulum Ca2+-ATPase pump (SERCA) [9].
• In comparison, less than 26% showed reactivity for alkaline phosphatase, a marker of fibroblastoid reticulum cells [10].

Chemical compound and disease context of Reticulum

• The 3-methyl analogue, 8-carbamoyl-3-methylimidazo[5,1-d]-1,2,3,5-tetrazin-4(3H)-one (CCRG 81045), was investigated further and found to possess good activity, when administered i.p., against the L1210 and P388 leukemias, the M5076 reticulum cell sarcoma, B16 melanoma, and ADJ/PC6A plasmacytoma [11].
• When accumulation of a malfolded protein in the endoplastic reticulum (ER) is induced by various adverse conditions, such as hypoxia, glucose starvation, and perturbation of calcium homeostasis, cells respond to the stress by increasing transcription of genes encoding ER molecular chaperones, a process known as unfolded protein response [12].
• I-A antigens isolated from SJL reticulum cell sarcoma (RCS) cells show greater heterogeneity with respect to charge and size of the A alpha chains than do I-A antigens isolated from normal SJL spleen cells [13].
• Recent experimental evidence indicates that Escherichia coli heat-labile enterotoxin and the closely related cholera toxin gain access to intracellular target substrates through a brefeldin A-sensitive pathway that may involve retrograde transport through the Golgi-endoplasmic reticulum network [14].
• We report regression of highly malignant reticulum cell sarcomas (J774) after liposome-mediated gene transfer in vivo [15].

Biological context of Reticulum

• Thapsigargin, an inhibitor of sarcoendoplasmic reticulum Ca2+-ATPases (SERCA), caused a time- and concentration-dependent decrease in the viability of MIN6 cells and an increase in DNA fragmentation and nuclear chromatin staining changes characteristic of apoptosis [16].
• Junctate, an integral calcium binding protein of endo(sarco)plasmic reticulum membrane, (a) induces and/or stabilizes peripheral couplings between the ER and the plasma membrane, and (b) forms a supramolecular complex with the InsP(3)R and the canonical transient receptor potential protein (TRPC) 3 calcium entry channel [17].
• These phenotypic changes were associated with up-regulation of sarco(endo)plasmic reticulum calcium ATPase (SERCA) 2a expression as well as decreased Na(+)/Ca(2+) exchanger, beta-myosin heavy chain, and sarcolipin (SLN) expression [18].
• Sarco(endo)plasmic reticulum Ca2+ ATPase (SERCA) gene silencing and remodeling of the Ca2+ signaling mechanism in cardiac myocytes [19].
• Morphologic observation of the neonatal RBCs established the fact that only puckered RBCs that exhibited brilliant cresyl blue staining reticulum were capable of undergoing receptor-mediated endocytosis of transferrin [20].

Anatomical context of Reticulum

• Association of alkaline-phosphatase-positive reticulum cells in bone marrow with granulocytic precursors [21].
• Chloride cells are characterized by an extensive tubular reticulum which is an extension of the basolateral plasma membrane [22].
• We identified slowly dividing cells among the Notch1-expressing stellate reticulum cells in specific locations near the basal epithelial cells expressing lunatic fringe, a secretory molecule modulating Notch signaling [23].
• Our studies show that mitochondria of cells grown on medium containing glycerol as the only carbon source, as opposed to glucose-grown cells, exhibit a strongly branched tubular reticulum [24].
• In striated muscle, the sarco(endo)plasmic reticulum Ca2+ ATPase (SERCA) plays an important role in terminating Ca2+ transients by returning cytosolic Ca2+ to intracellular stores [19].

Associations of Reticulum with chemical compounds

• In contrast in the freshwater-adapted fish the chloride cell's tubular reticulum is separated by deep apical junctions from the external environment [22].
• Both responses were significantly reduced by pre-treatment with sarco-endoplasmic reticulum Ca(2+) ATPase (SERCA) pump inhibitors or with the intracellular Ca(2+) chelator BAPTA-AM [25].
• In addition, class II MHC and Lamp 1 were co-localized in vesicles of the trans Golgi reticulum, where they were segregated from 46-kD mannose-6-phosphate receptors [26].
• Subcellular fractionation and studies with the antibiotic monensin indicate that the processing events occur in the Golgi-endoplasmic reticulum compartment of U-2 OS cells [27].
• The high ouabain affinity Na+ pumps may thereby modulate reticulum Ca2+ content and Ca2+ signaling [28].

Gene context of Reticulum

• Here, we show that Sys1p is an integral membrane protein that resides on a post-endoplasmic reticulum (ER) organelle(s) [29].
• Sarcolipin regulates sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA) by binding to transmembrane helices alone or in association with phospholamban [30].
• Phospholamban (PLN), a regulator of sarco(endo)plasmic reticulum Ca(2+)-ATPases (SERCAs), interacts with both the cytosolic N domain and transmembrane helices M2, M4, M6, and M9 of SERCA [30].
• Cardiac-specific overexpression of sarcolipin inhibits sarco(endo)plasmic reticulum Ca2+ ATPase (SERCA2a) activity and impairs cardiac function in mice [31].
• Overexpression of PCSK9 accelerates the degradation of the LDLR in a post-endoplasmic reticulum compartment [32].

Analytical, diagnostic and therapeutic context of Reticulum

• Immunoelectron microscopy with peroxidase-labeled second antibody demonstrates that the varicosities are surrounded by a subsynaptic reticulum, that they contain immunoreactive vesicles of about 30-50 nm, and thus probably represent synaptic release sites [33].
• Dissection of the functional differences between sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA) 1 and 3 isoforms by steady-state and transient kinetic analyses [34].
• The level of electrical discharge in the reticulum and rumen in the first 3 days after vagotomy was increased progressively with distension without giving rise to the large group discharges characteristic of the long-term vagotomized sheep, and was reduced by atropine (0.1-1 mg kg-1) but not by hexamethonium (2 mg kg-1) [35].
• Western blotting analysis revealed higher levels of sarco(endo)plasmic reticulum Ca(2+)-ATPase (SERCA) 1 ( approximately 150%) Ca(2+) pump isoform, unaltered levels of SERCA2 Ca(2+) pump isoform, and lower levels of PLN ( approximately 50%) and delta-, beta-, and gamma-CaM kinase II (40 approximately 70%) in soleus of the hyperthyroid rabbit [36].
• Immunocytochemistry showed that EGF receptor was present on the surface of many but not all of the cultured stellate reticulum cells [37].

References