2024-03-29T00:30:04Zhttp://digital.csic.es/dspace-oai/requestoai:digital.csic.es:10261/551512020-11-12T14:28:29Zcom_10261_22com_10261_1col_10261_275
Conformational signals in the C-terminal domain of methionine adenosyltransferase I/III determine its nucleocytoplasmic distribution
Reytor, Edel
Pérez-Miguelsanz, Juliana
Álvarez, Luis
Pérez-Sala, Dolores
Pajares, María A.
Methionine adenosyltransferase
Nucleocytoplasmic localization
El pdf del artículo es la versión pre-print.
The methyl donor S-adenosylmethionine is synthesized in mammalian cytosol by three isoenzymes. Methionine adenosyltransferase II is ubiquitously expressed, whereas isoenzymes I (homotetramer) and III (homodimer) are considered the hepatic enzymes. In this work, we identified methionine adenosyltransferase I/III in most rat tissues both in the cytoplasm and the nucleus. Nuclear localization was the preferred distribution observed in extrahepatic tissues, where the protein colocalizes with nuclear matrix markers. A battery of mutants used in several cell lines to decipher the determinants involved in methionine adenosyltransferase subcellular localization demonstrated, by confocal microscopy and subcellular fractionation, the presence of two partially overlapping areas at the C-terminal end of the protein involved both in cytoplasmic retention and nuclear localization. Immunoprecipitation of coexpressed FLAG and EGFP fusions and gel filtration chromatography allowed detection of tetramers and monomers in nuclear fractions that also exhibited S-adenosylmethionine synthesis. Neither nuclear localization nor matrix binding required activity, as demonstrated with the inactive F251D mutant. Nuclear accumulation of the active enzyme only correlated with histone H3K27 trimethylation among the epigenetic modifications evaluated, therefore pointing to the necessity of methionine adenosyltransferase I/III to guarantee the supply of S-adenosylmethionine for specific methylations. However, nuclear monomers may exhibit additional roles.
This work was supported by grants of the Ministerio de Educación y Ciencia (BMC2002-0243 and BFU2005-00050 to MAP and SAF2006-03489 to DPS) and the Instituto de Salud Carlos III (RCMN C03/08 to MAP and RD07/0064/0007 to DPS).
Peer reviewed
2012-08-28T15:19:14Z
2012-08-28T15:19:14Z
2009
artículo
http://purl.org/coar/resource_type/c_6501
FASEB Journal 23(10): 3347-3360 (2009)
0892-6638
http://hdl.handle.net/10261/55151
10.1096/fj.09-130187
1530-6860
en
http://dx.doi.org/10.1096/fj.09-130187
open