R proteins

Food vitamin B 2 appears to bind to a saUvary transport protein referred to as the R-protein, R-binder, or haptocorrin. In the stomach, R-protein and the intrinsic factor competitively bind the vitamin. Release from the R-protein occurs in the small intestine by the action of pancreatic proteases, leading to specific binding to the intrinsic factor. The resultant complex is transported to the ileum where it is bound to a cell surface receptor and enters the intestinal cell. The vitamin is then freed from the intrinsic factor and bound to transcobalamin II in the enterocyte. The resulting complex enters the portal circulation. 

Sadler, A. J., Micanovic, R., Katzenstein, G. E., Lewis, R. V., and Middaugh, C. R., Protein conformation and reversed-phase high-performance liquid chromatography, /. Chromatogr, 317, 93, 1984. 

Jaenicke R, Seckler R. Protein misassembly in vitro. Adv. Protein Chem. 1997 50 1-59. 

Filbin, M. T., D Urso, D., Zhang, K., Wong, M., Doyle, J. P. and Colman, D. R. Protein zero of peripheral nerve myelin adhesion properties and functional models. Adv. Mol. Cell. Biol. 16 159-192,1996. 

FIGURE 24-2 Tyrosine phosphorylation and dephosphorylation. Protein tyrosine kinases (PTK) catalyze the transfer of the y-phosphate group from ATP to the hydroxyl group of tyrosine residues, whereas protein tyrosine phosphatases (PTP) remove the phosphate group from phosphotyro-sine. R, protein. 

M. R. Protein quality control Triage by chaperones and proteases. Genes e[ Development 1997, 11, 815-823. 

Ma, B. Elkayam, T. Wolfson, H. Nussinov, R. Protein-protein interactions structurally conserved residues distinguish between binding sites and exposed protein surfaces. Proc. Natl Acad. Sci. USA 2003, 100, 5772-5777. 

Scopes, R. Protein Purification Principles and Practice Springer-Verlag New York, NY, 1982. 

X-Protein. Amyloid p i 42 peptide and r-protein have a clinical significance as early diagnostic markers in Alzheimer s disease (AD), and its evaluation is mandatory for efficient treatment. The mean levels of A/3i 42 and r-protein in CSF were significantly reduced (with high specificity and sensitivity) in patients in comparison to normal findings (M6). 

Bianco et al. [34] CNT-r proteins (fibrinogen, protein A, erythropoietin, and apolipoprotein) CNT-TEG-short protein complex quickly entered fibroblasts and other cells, sometimes migrated to their nuclei. Proteins executed their normal biological functions... 

Baudier, J. Cole, R.D. Phosphorylation of r proteins to a state like that in Alzheimers brain is catalyzed by a calcium/calmodulin-dependent kinase and modulated by phospholipids. J. Biol. Chem., 262, 17577-17583 (1987)... 

M. Uchida, T. Imahori, K. r protein kinase I converts normal tau protein into A68-like component of paired helical filaments. J. Biol. Chem., 267, 10897-10901 (1992)... 

ATP 4- protein r <1, 2, 4, 5> (<5> microtubule-associated protein, enzyme can also phosphorylate human tau [1] <1> phosphorylates r and forms paired helical filament epitopes, r/Kl, K2, K3 and t/4 repeat [6] <2> enzyme can also phosphorylate bovine tau [4] <2> phosphorylates r protein into Alzheimer disease-like forms, resulting in neuronal death [7] <2> 6 isoforms of human r expressed in adult human brain [12] <2> when a / -mediated aggregated r is used as a substrate for TPKII, an 8fold increase in the rate of TPKII-mediated r phosphorylation is observed... 

Takahashi, M. Tomizawa, K. Ishiguro, K. Takamatsu, M. Fujita, S.C. Imahori, K. Involvement of r protein kinase I in paired helical filament-like phosphorylation of the juvenile r in rat brain. J. Neurochem., 64, 1759-1768 (1995)... 

Hoshi, M. Takashima, A. Noguchi, K. Murayama, M. Sato, M. Kondo, S. Saitoh, Y. Ishiguro, K. Hoshino, T. Imahori, K. Regulation of mitochondrial pyruvate dehydrogenase activity by r protein kinase I/glycogen synthase kinase 3/1 in brain. Proc. Natl. Acad. Sci. USA, 93, 2719-2723 (1996)... 

Evans, D.B. Rank, K.B. Bhattacharya, K. Thomsen, D.R. Gurney, M.E. Sharma, S.K. t Phosphorylation at serine 396 and serine 404 by human recombinant r protein kinase II inhibits fs ability to promote microtubule assembly. J. Biol. Chem., 275, 24977-24983 (2000)... 

The r-protein operons are regulated primarily through a translational feedback mechanism. One r-protein encoded by each operon also functions as a translational repressor, which binds to the mRNA... 

The R proteins, which act as receptors for Avr, and other elicitor proteins, are usually leucine-rich-repeat proteins with a characteristic nucleotide binding site attached (NB-LRR proteins).534,537 Like other cell surface receptors they participate in signaling and utilize both ion channels and Ser/Thr protein kinases.538 The Arabidopsis genome contains 150 sequences that may represent NB-LRR receptors.530... 

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