Liver Endoplasmic reticulum

Moebius, F.F., Hanner, M., Knaus, H.G., Weber, F., Striessnig, J., and Glossmann, H. (1994) Purification and amino-terminal sequencing of the high affinity phenylalkylamine Ca2+ antagonist binding protein from guinea pig liver endoplasmic reticulum./. Biol. Chem. 269, 29314-29320. 

Bourdi, M. et al., Anti-liver endoplasmic reticulum autoantibodies are directed against human cytochrome P-450IA2. A specific marker of dihydralazme-induced hepatitis, J. Clin. Invest., 85, 1967, 1990. 

Reynolds ES. 1972. Comparison of early injury to liver endoplasmic reticulum by halomethanes, hexachloroethane, benzene, toluene, bromobenzene, ethionine, thioacetamide and dimethylnitrosamine. 

Long RM, Moore L. 1986b. Inhibition of liver endoplasmic reticulum calcium pump by CCH and release of a sequestered calcium pool. Biochem Pharmacol 35 4131-4137. 

Daniele, N. Rajas, F Payrastre, B. Mauco, G. Zitoun, C. Mithieux, G. Phosphatidylinositol 3-kinase translocates onto liver endoplasmic reticulum and may account for the inhibition of glucose-6-phosphatase during refeeding. J. Biol. Chem., 274, 3597-3601 (1999)... 

Biosynthesis of cholesteryl esters. The acyl-CoA cholesterol acyltransferase involved in cholesteryl ester synthesis is located on the cytosolic surface of liver endoplasmic reticulum. 

A number of other cytochromes are located in the intermembrane space and the inner surface of the outer mitochondrial membrane. Cyt bs (cytochrome b ) is a small heme protein with a hydrophihc domain of about 95 amino acids and a carboxyl terminus of about 45 hydrophobic amino acids that serve to anchor the protein to the inner surface of the outer mitochondrial membrane. Cyt bs is reduced by NADH-cyt bs reductase, also located on the inner surface of the outer membrane. Under conditions of high intermembrane ionic strength, Cc is released from the inner membrane, and can transport electrons from cyt bs on the outer membrane to CcO on the inner membrane. Cyt bs contains protoheme b with the iron atom hgated by two histidine nitrogen atoms. The heme group has a reduction potential of -1-10 mV versus NHE. Cyt bs is also found on the liver endoplasmic reticulum membrane, where it transfers electrons from NADH-cyt b ... 

Meissner G. Ionic permeability of isolated muscle sarcoplasmic reticulum and liver endoplasmic reticulum vesicles. Methods En-zymol. 1988 157 417-437. 

The transfer of the information described in the preceding sections of this chapter to the in vivo situation is a matter where opinions are sharply divided, even if more than 20 years have elapsed since the discovery by Vasington and Murphy [4]. One key problem, naturally, is the impossibility of reproducing the composition and the conditions of the cytosol in in vitro experiments. The above mentioned effect of Mg on the rate of Ca influx into mitochondria is but one striking example of the difficulties inherent to the extrapolation to the in situ conditions. Of interest in this respect are recent experiments [124,125] in which methods have been devised to estimate simultaneously the membrane potential across the plasma membrane and the mitochondria of nerve endings in situ. The conclusion of this work has been that the concentration of free Ca in the cytosol correlates directly to the membrane potential across the mitochondrial membrane, and is maintained at a steady-state level below 1 jaM. Simulation of the in situ conditions has also been the aim of studies [126] in which isolated liver endoplasmic reticulum has been added to media in which isolated liver mitochondria were made to take up Ca, or in which liver cells have been treated with digitonin to abolish the permeability barrier of the plasma membrane. It was found that respiring mitochondria lower the external Ca " concentration to about 0.5 /iM. The addition of endoplasmic reticulum vesicles produces a further decrease of the external Ca " to about 0.2 jaM. Thus, mitochondria... 

As mentioned previously, the biotransformation of lipophilic xenobiotics by Phase I and Phase II reactions might be expected to produce a stable, water-soluble, and readily excretable compound. However, there are examples of hepatic biotransformation mechanisms by which xenobiotics are converted to reactive electrophilic species. Unless detoxified, these reactive electrophiles may interact with a nucleophilic site in a vital cell constituent, leading to cellular damage. There is evidence that many of these reactive substances bind covalently to various macromolecular constituents of liver cells. For example, carbon tetrachloride, known to be hepatotoxic, covalently binds to lipid components of the liver endoplasmic reticulum (Reynolds and Moslen 1980). Some of the reactive electrophiles are carcinogenic as well. 

The answer is d. (Murray, pp 123—148. Scriver, pp 2367—2424. Sack, pp 159—175. Wilson, pp 287-317.) Some monooxygenases found in liver endoplasmic reticulum require cytochrome P450. This cytochrome acts to transfer electrons between NADPH, O2, and the substrate. It can be an electron acceptor from a flavoprotein. In the mitochondrial electron transport chain, flavoproteins donate electrons to coenzyme Q, which then transfers them to other cytochromes. Flavoproteins that are oxidases often react directly with molecular oxygen to form hydrogen peroxide. Flavoproteins can be NADH dehydrogenases that oxidize NADH and transfer the electrons to coenzyme Q. The electron transfer centers of flavoproteins in the electron transport chain contain nonheme iron and sulfur. 

REYNOLDS, E.S. (1971) Liver endoplasmic reticulum Target site of halocarbon metabolites. Adv. Exp. Med. Biol., 84, 117. 

Weng, S., and Spiro, R. G. (1993). Demonstration that a kifunensin-resistant a-mannosidase with a processing action on N-linked oligosaccharides occurs in rat liver endoplasmic reticulum and various cultured cells. J. Biol. Chem. 268, 25656-25663. 

Brown, C. A., 8c Black, S. D. (1989). Membrane topology of mammalian cytochrome P-450 from liver endoplasmic reticulum determination by trypsinolysis of Phenobarbital-treated microsomes. The Journal of Biological Chemistry, 264, 4442-4449. 

Tienilic acid is a uricosuric diuretic drug that may cause immunoallergic hepatitis in 1 in 10 000 patients, a side-effect that resulted in its withdrawal from circulation. The immunoallergic hepatitis was associated with the appearance of circulating anti-reticulum antibodies, called anti-LKM2 antibodies, which are directed towards a liver endoplasmic reticulum protein. From these observations, the mechanism of the immunotoxicity associated with the prolonged use of tienilic acid was elucidated by the Mansuy group. ... 

Bourdi, M., Demady, D., Martin, J.L., Jabbour, S.K., Martin, B.M., Geoige, J.W. Pohl, L.R. (1995) Arch. Biochem. Biophys., 323, 397-403. cDNA cloning and baculovirus expression of the human liver endoplasmic reticulum p58 characterization as a protein disulfide isomerase isoform, but not as a protease or a carnitine acyltransferase. 

Clissold, P. M. and Bishop, J. O. 1981. Molecular cloning of cDNA sequences transcribed from mouse liver endoplasmic reticulum poly(A) mRNA, Gene, 15, 225-235. 

Remmer H, Merker HJ (1963) Drug-induced changes in the liver endoplasmic reticulum association with drug-metabolizing enzymes. Science 142 1657-1658... 

Bischoff, J., K. Moremen, and H. F. Lodish, Isolation, characterization, and expression of cDNA encoding a rat liver endoplasmic reticulum a-mannosidase, J. Biol Chem., 1990, 265, 17110-17117. 

Fructose 1,6-bisphosphate aldolase Cytoplasm Rat liver endoplasmic reticulum... 

Animals Fed barbiturates Liver endoplasmic reticulum proliferates... 

---