RBP-J

The Wnt pathway is suppressive to Notch. For deciphering who is the oncogene, and who is the suppressor, click Valdez et al Cell Stem Cell 2012 11 676-88. For failure of RBP-J dendritic cells to respond to TLR T lymphocyte receptors, click Chen YR et al Mol Biol Rep 2013 40 1531-9. 

Beres TM, Masui T, Swift GH, Shi L, Henke RM, MacDonald RJ. PTFl is an organ-specific and Notch-independent basic helix-loop-helix eomplex containing the mammalian Suppressor of Hairless (RBP-J) or its paralogue, RBP-L. Mol Cell Biol. 2006 26 117-30. 

Feng F, Wang YC, Hu XB, Liu G, Chen YR, Wang L, He F, Dou GR, Liang L, Zhang HW, Han H. The transcription factor RBP-J-mediated signaling is essential for dendritic cells to evoke efficient anti-tumor immune responses in mice. Mol Cancer. 2010 9 90. 

RbP RbjP RbjPy Rb4P RbP, RbP RbP.j ReyP ReP RejP4 RcjPs Re i3 Re Pp ReP, RhyP RhjPy RI14P3 RhP,... 

Yamamoto N et al (2003) Notch/RBP-J signaling regulates epidermisfhair fate determination of hair follicular stem cells. Curr Biol 13(4) 333-338... 

The tissue distribution and levels of RBP in normal and in retinol-deficient rats were measured in order to explore the role of different tissues in the metabolism of RBP (J. E. Smith et al., 1975). The tissues examined included liver, kidney, fat, muscle, brain, eye, salivary gland, thymus, lung, heart, intestine, spleen, adrenal, testes, thyroid, and red blood cells. The RBP levels were low or very low in tissues other than liver, kidney, and serum and varied from 12 p.g/g of tissue for normal spleen to an undectable level in red blood cells. Much of the RBP in the tissues with low levels was most likely due to residual serum in the samples. In general, except for liver, RBP levels were lower in tissues from retinol-deficient rats than in those fixim normal rats. In normal rats, the liver, kidney, and serum levels were 30 4 (mean SEM), 151 22, and 44 3 p.g/g, respectively. In retinol-deficient rats, the liver RBP level was about three times the normal level whereas the kidney and serum levels were about one-fifth the normal values. It was suggested that die levels of RBP in normal as compared to deficient liver, serum, and kidney appear to reflect the relative rates of RBP secretion and turnover (see later discussion). 

Palmeri D, Carroll KD, Gonzalez-Lopez O, Lukac DM. Kaposi s sarcoma-associated herpesvirus Rtatetramers make high-affinity interactions with repetitive DNA elements in the Mta promoter to stimulate DNA binding of RBP-Jk/CSL. J Virol. 2011 85 11901-15. 

Minoguehi S, Ikeda T, Itohara S, Kaneko T, Okaiehi H, Honio T. Studies on the cell-type specifie expression of RBP-L a RBL-L family member, by replacement insertion of beta-galactosidase. J Bioehem. 1999 126 738-47. 

Jaconi, S., Saurat, J. H., and Siegenthaler, G. 1996. Analysis of normal and truncated holo-and apo-retinol binding protein (RBP) in human serum Altered ratios in chronic renal failure. EurJ Encrinol 134 576-582. 

Quadro, L., Blaner, W. 8., Hamberger, L. et al. 2002. Muscle expression of human retinolbinding protein (RBP). 8uppression of the visual defect of RBP knockout mice. J Biol Chem 277 30191-30197. 

Zinc deficiency accompanied by a depression in plasma retinol has been noted in several studies. Some investigators have reported an increased liver vitamin A in several species of zinc-deficient animals (Stevenson and Earle, 1956 Saraswat and Arora, 1972 J. C. Smith et aL, 1973, 1976 Brown et aL, 1976 Jacobs et al., 1978 Carney et aL, 1976). There are also reports in humans in an association between lowered zinc, retinol, and RBP (Jacobs et a/., 1978 Solomons and Russell, 1980). J. C. Smith et al, (1973) suggested that hepatic mobilization of vitamin A was impaired by zinc deficiency and their follow-up studies demonstrated a depression in liver and plasma RBP in the zinc-deficient rat compared to pair-fed controls (Brown et al., 1976 Smith et al., 1974). The depression was hypothesized to be the result of a depressed synthesis rather than an increased turnover of RBP. That preformed RBP is present in zinc-deficient rats was demonstrated by Carney et al. (1976) using labeled vitamin A. Zinc-deficient rats, whether or not they were also vitamin A-deficient, were able to mobilize over a short time span a small oral dose of vitamin A as well as could their pair-fed controls. Those animals deficient only in zinc excreted metabolites of the labeled vitamin in a similar quantitative manner as the pair-fed controls for 6 days postdosing. These data suggest that the release of retinol from retinyl ester stores, as well as a depressed RBP synthetic rate, contributed to low plasma levels of vitamin A in zinc deficiency. 

Extensive studies conducted during the past decade have demonstrated that the availability of retinol to the liver cell plays a critical role in the control of RBP secretion from the cell. The effects of retinol depletion and of retinol repletion are illustrated in Fig. 4. In the retinol-deficient state, the secretion of RBP from the liver is blocked, resulting in the accumulation of an enlarged pool of apo-RBP in the liver, and a concomitant decline in serum RBP level (Muto et al., 1972 J. E. Smith et al., 1973a). Conversely, repletion of retinol-deficient rats with retinol stimulates the rapid secretion of RBP from the expanded liver pool into the plasma. 

The roles of various subcellular organelles and structures in the hepatic metabolism and secretion of RBP have been studied with both normal and retinol-deficient rats. These studies have employed assays for a variety of marker enzymes and other constituents. After differential centrifugation of liver homogenates, 79 1% of the RBP was found associated with the liver microsomes (Harrison et al., 1979). Similar proportions of total liver RBP were found in the microsomal fractions of livers from both normal and retinol-deficient rats (J. E. Smith et al., 1975). Further subfractionation of the microsomal fraction showed that RBP was particularly enriched in the rough microsomal fraction (3.8 0.5-fold over the homogenate), which contained 49 4% of the liver microsomal RBP (Smith and Goodman, 1979). RBP was also enriched in the smooth microsomal fraction (3.2 0.2-fold over the homogenate). 

Plasma retinoic acid transport was studied with vitamin A-deficient rats maintained on small doses of radioactively labeled retinoic acid (J. E. Smith et al., 1973b). On polyacrylamide gel electrophoresis almost all of the recovered radioactivity migrated with serum albumin. Similar results were obtained with serum from a normal control rat given a single oral dose of [ CJretinoic acid. These findings indicated that retinoic acid is transported in rat plasma bound to albumin, and not by RBP. 

Frank J, Beck SC, Sellinger M, Wissinger M, Zemner E, Biesalski HK (1998) Biochemical vitamin A deficiency as a result of a mutation of the RBP gene. FASEB J 12 A352... 

MacKenzie, E Duriez, P Wong, F. Noseda, M. Karsan, A. Notch4 inhibits endothelial apoptosis via RBP-Jkappa-dependent and -independent pathways. J. Biol. Chem. 2004,279,11657-11663. 

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