Soluble Liver Antigen/Liver and Pancreas, an Antigen in Autoimmune Hepatitis Patients: Influence on Selenocysteine Synthesis and its Complex with HSP70

Autor:	Yasuko Murakami, Takashi Osaka, Takashi Shinkawa, Asuka Hattori, Senya Matsufuji, Toshiaki Isobe, Tamiko Matsufuji, Yuta Tanaka, Takaharu Mizutani
Rok vydání:	2007
Předmět:	chemistry.chemical_classification Expression vector Health Toxicology and Mutagenesis fungi Autoantibody Autoimmune hepatitis Transfection Biology Toxicology medicine.disease Molecular biology Titer chemistry Biochemistry Antigen biology.protein medicine Selenoprotein Antibody
Zdroj:	JOURNAL OF HEALTH SCIENCE. 53:682-691
ISSN:	1347-5207 1344-9702
Popis:	Autoimmune hepatitis (AIH) serum contains autoantibodies against solubl el iver antigen/liver and pancreas (SLA/LP), a protein that interacts with the selenocysteine (Sec)-tRNA Sec .W e investigated the infl uence of AIH serum on Sec production. Two (#3 and #4) of four AIH sera inhibited its synthesis, with serum #4 showing the strongest inhibition. This did not parallel the level of antibodies to SLA/LP (anti-SLA/LP) in sera, because the titer in serum #3 was higher than that in serum #4. Thus, w ef ound that AIH inhibited Sec synthesis but we could not conclude that this inhibition depended on an autoantibody against SLA/LP. To clarify the function of SLA/LP, we prepared an antibody against an SLA/LP peptide. Inhibition of Sec synthesis by this anti-peptide antibody was incomplete and sometimes did not occur. Absorption of autoantibodies in the AIH serum with the SLA/LP protein did not have any effects on Sec synthesis by Sec synthase (SecS) which converts Seryl (Ser)-tRNA Sec to Sec-tRNA Sec .W e then used SLA/L Pi nstead of active bovine SecS but we could not detect SecS activity in SLA/LP itself. Next, we studied the distribution of SLA/LP in HEK293 cells transfected with an SLA/LP expression vector. Immunofluorescence microscopy detected SLA/LP expression in the cytoplasm, but not the nucleus of HEK293 cells. Higher levels of SLA/LP in the cytosol did not correlate with higher Sec production, which remained identical to mock-transfected cells. Interestingly, we found that S LA/LP formed a complex in the cytosol of HEK293 cells. This complex was purified and the components analy zed using Nano-LC and MS/MS, which we identified as HSP7 0a nd tubulin. Altogether, our data suggest that SLA/LP may play an indirect role to produce Sec in the selenoprotein synthesis machinery.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::7cc0694d9859aa67fabe976becfc94ed https://doi.org/10.1248/jhs.53.682 Zobrazit plný text záznamu