Serine residues 994 and 1023/25 are important for insulin receptor kinase inhibition by protein kinase C isoforms beta2 and theta

AIMS/HYPOTHESIS: Inhibition of the signalling function of the human insulin receptor (HIR) is one of the principle mechanisms which induce cellular insulin resistance. It is speculated that serine residues in the insulin receptor beta-subunit are involved in receptor inhibition either as inhibitory phosphorylation sites or as part of receptor domains which bind inhibitory proteins or tyrosine phosphatases. As reported earlier we prepared 16 serine to alanine point mutations of the HIR and found that serine to alanine mutants HIR-994 and HIR-1023/25 showed increased tyrosine autophosphorylation when expressed in human embryonic kidney (HEK) 293 cells. In this study we examined whether these mutant receptors have a different susceptibility to inhibition by serine kinases or an altered tyrosine kinase activity. METHODS: Tyrosine kinase assay and transfection studies. RESULTS: In an in vitro kinase assay using IRS-1 as a substrate we could detect a higher intrinsic tyrosine kinase activity of both receptor constructs. Additionally, a higher capacity to phosphorylate the adapter protein Shc in intact cells was seen. To test the inhibition by serine kinases, the receptor constructs were expressed in HEK 293 cells together with IRS-1 and protein kinase C isoforms beta2 and theta. Phorbol ester stimulation of these cells reduced wild-type receptor autophosphorylation to 58 % or 55 % of the insulin simulated state, respectively. This inhibitory effect was not observed with HIR-994 and HIR-1023/25, although all other tested HIR mutants showed similar inhibition induced by protein kinase C. CONCLUSION/INTERPRETATION: The data suggest that the HIR-domain which contains the serine residues 994 and 1023/25 is important for the inhibitory effect of protein kinase C isoforms beta2 and theta on insulin receptor autophosphorylation.

Na 50 Nachlass Arthur Schopenhauer - 'Schopenhauer-Archiv', 994 - Fragen von Eduard Grisebach im Zusammenhang der veröffentlichten Schopenhauer-Biographie

u.a. Johanna Schopenhauer und Wirken in Braunschweig; Autobiographie von Adele Schopenhauer; Arthur Schopenhauer in Göttingen; Ottilie von Goethe;

Ms. Ff. Mus. 994 - V. post Trinit.

da me Telemann

(Table 1) Porosity, particle diameter, ATP content and carbon and nitrogen composition of ODP Site 164-994 sediments

Sediment samples were obtained for detailed Adenosine 5'-Triphosphate (ATP) analysis down to 57.8 m below the seafloor (mbsf). The samples were also analyzed for particle-size distribution, calcium carbonate (CaCO3), organic carbon, and total nitrogen. The concentrations of ATP ranged between 360 and 7050 pg/g (dry weight sediment), which agree well with a limited number of direct bacteria counts. Principal component analyses show that 63% of the total variance can be accounted for by the first two principal components. The concentration of ATP (bacterial numbers by inference) is virtually independent of the concentration of sedimentary organic carbon, but correlates with CaCO3 and coarse particles.

Operator's, organizational, direct support, and general support maintenance manual for semitrailer, tank, fuel, 5000 gallon, 4 wheel, M131A4 (NSN 2330-00-994-9459), M131A5 (NSN 2330-00-226-6079), semitrailer, tank, fuel servicing, 5000 gallon, 4 wheel, M131A4C (NSN 2330-00-994-9458) ....

"June 1992."

Hand recipt manual covering the end item/Components of End Item (COEI). Basic Issue Items (BII), and Additional Authorization List (ALL) for semitrailer, tank, fuel, 5,000 gal., 4 wheel, M131A4 (NSN 2330-00-994-9459) ... M131A5C (NSN 2330-00-226-6080).

"December 1978."