Disease relevance of SSR1

• All tissues were SS-receptor positive for either radioligand, except the thymomas [1].
• Fifty-four of 62 carcinoid patients had SS receptor-positive tumors (87%) [2].
• The recently described ss receptor for estrogen has not been analyzed in angiofibroma [3].
• This new SS receptor imaging method may help the clinicians for the localization of the primary tumor and its metastases, for the staging of certain tumors, to predict a successful SS therapy, and as a prognostic or differential diagnostic marker [4].
• Loss of heterozygosity at the SS receptor type 5 locus in human GH- and TSH-secreting pituitary adenomas [5].

High impact information on SSR1

• Ca(2+) + A23187-induced K(+)-permeabilization of SS R1 fractions revealed a similar fraction of cal-res cells, whose (86)Rb uptake showed both high Na/K pump and leak fluxes. val-res/cal-res RBCs might represent either a distinct erythroid genealogy, or an "end-stage" of normal and SS RBCs [6].
• All tumors except one from patients pretreated with octreotide (3 days to 3.8 years) were SS receptor positive [2].
• The majority of the eight SS receptor-negative carcinoids were mainly bronchial carcinoids (n = 5), usually poorly differentiated [2].
• Surprisingly, pgp25 (SSR alpha) also bound Ca2+ although gp25H (SSR beta) and gp25L did not [7].
• SSR alpha and associated calnexin are major calcium binding proteins of the endoplasmic reticulum membrane [7].

Chemical compound and disease context of SSR1

• In the majority of carcinoids or islet cell carcinomas, the SS receptor status correlated with the in vivo biochemical response (hormone inhibition) to octreotide [2].
• Patients underwent dobutamine echocardiography (DE) and rest scintigraphic studies before revascularization and DE at 3 to 4 months. alpha- and ss-receptor density (ARD and BRD) and extent of fibrosis were quantified from the myocardial biopsies [8].

Biological context of SSR1

• These results provide further evidence for a functional differentiation of rough and smooth ER and for a role of SSR in protein translocation across the ER membrane [9].
• Both were shown to be phosphorylation sites; Y775 was only marginally phosphorylated in cells expressing the wild-type ss-receptor, whereas Y778 was phosphorylated at higher stoichiometry [10].
• 1) As this tumor displayed a high immunoreactivity for sst3 and the cultured tumor cells expressed the sst3 mRNA only, this SSR may be the subtype involved in the inhibition of epithelial tumor cell proliferation by octreotide in vitro [11].
• Scarce information is available so far on the SS-R subtype expression pattern as well as on the second messenger systems linked to SS-R activation in human lymphoid cells [12].
• It is concluded that (i) the SSR holds; (ii) dichoptic (and monocular) edges are seen at the horopter; (iii) the vergence fine tuning prevents superposition of dichoptic edges even if this causes a fixation disparity [13].

Anatomical context of SSR1

• The signal sequence receptor (SSR), an integral membrane glycoprotein of 34 kDa, has previously been shown to be a component of the molecular environment which nascent polypeptide chains meet in passage through the endoplasmic reticulum (ER) membrane [9].
• We have used antibodies directed against the SSR and both immunocytochemistry and cell fractionation to determine its distribution in rat liver cells [9].
• We investigated the SS distribution and SS-R expression pattern in the normal human thymus using autoradiography, membrane homogenate binding studies, and RT-PCR [14].
• SS-R have been demonstrated in vivo and in vitro on cells from endocrine and immune systems [14].
• Moreover, the activation of lymphoid cells seems to modify their SS-R expression pattern [15].

Associations of SSR1 with chemical compounds

• This lipid kinase binds to phosphorylated tyrosine residues Y740 and Y751 in the kinase insert of the human platelet-derived growth factor ss-receptor [10].
• Substitution of serum with a synthetic replacement (Medi-CultR SSR 1 and 2), lacking hormones, cholesterol and growth factors, led to a minimal output of progesterone from granulosa-luteal cells [16].
• In contrast, all SS receptor-positive tumors simultaneously contained steroid receptors [17].
• Specific intra-tissue responses to manganese in the floating lamina of Trapa natans L [18].
• Carbofuran residue in water, soil, and Trapa fruits, after field application [19].

Regulatory relationships of SSR1

• The amplitude of the SSR generated by the second stimulus (SSR2) was expressed as a percentage of that generated by the first (SSR1), and compared between control subjects and patients for each ISI [20].

Other interactions of SSR1

• The SSR amplitude recovery percentage, which was obtained by dividing the amplitude of SSR2 by the amplitude of SSR1, was significantly different on the cooled side [21].
• There are five distinct SS receptor (SSTR) subtypes, namely SSTR1-5, which show different affinities for SS14 and SS28 [22].
• However, not much is known with respect to the SS receptor subtype (sst) expression pattern and the expression of SS itself in the immune system [23].
• Cortistatin (CST)-14, a neuropeptide with high structural homology with somatostatine (SS)-14, binds all SS receptor subtypes but also shows activities not shared by SS [24].
• The receptors were specific for the respective peptide and of high affinity, with a dissociation constant (Kd) of 0.90 nM for SS receptor and 0.87 nM for gastrin receptors [25].

Analytical, diagnostic and therapeutic context of SSR1

• In conclusion, radiolabeled [DTPA0,Tyr3]octreotide and, especially, [DTPA0,Tyr3]octreotate and their DOTA-coupled counterparts are most promising for scintigraphy and radionuclide therapy of SS receptor-positive tumors in humans [26].
• The results were compared with SS receptor (sstr subtype profile (by Northern blot analysis) and the relative expression of the second subtype, sstr2 (by ribonuclease protection assay, RPA) [27].
• The SSR subtype expression pattern was studied in vitro on the surgically resected specimens by ligand binding techniques, quantitative reverse transcriptase polymerase chain reaction (RT-PCR) and immunohistochemistry [28].

References