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dc.contributor.authorSafran, Marjorie
dc.contributor.authorFarwell, Alan P.
dc.contributor.authorLeonard, Jack L.
dc.date2022-08-11T08:10:04.000
dc.date.accessioned2022-08-23T16:54:12Z
dc.date.available2022-08-23T16:54:12Z
dc.date.issued1996-07-05
dc.date.submitted2008-08-15
dc.identifier.citation<p>J Biol Chem. 1996 Jul 5;271(27):16363-8.</p>
dc.identifier.issn0021-9258 (Print)
dc.identifier.doi10.1074/jbc.271.27.16363
dc.identifier.pmid8663169
dc.identifier.urihttp://hdl.handle.net/20.500.14038/42448
dc.description.abstractType II iodothyronine 5'-deiodinase is an approximately 200-kDa multimeric enzyme in the brain that catalyzes the deiodination of thyroxine (T4) to its active metabolite, 3,5,3'-triiodothyronine. In astrocytes, cAMP stimulation is required to express catalytically active type II iodothyronine 5'-deiodinase. The affinity ligand N-bromoacetyl-L-T4 specifically labels the 29-kDa substrate-binding subunit (p29) of this enzyme in cAMP-stimulated astrocytes. To determine the requirements for cAMP-induced activation of this enzyme, we optimized N-bromoacetyl-L-T4 labeling of p29 in astrocytes lacking type II iodothyronine 5'-deiodinase activity and examined the effects of cAMP on the hydrodynamic properties and subcellular location of the enzyme. We show that the p29 subunit is expressed in unstimulated astrocytes and requires 10-fold higher concentrations of N-bromoacetyl-L-T4 to achieve incorporation levels equal to those of p29 in cAMP-stimulated cells. Gel filtration showed that p29 was part of a multimeric membrane-associated complex in both cAMP-stimulated and unstimulated astrocytes and that cAMP stimulation led to an increase of approximately 60 kDa in the mass of the holoenzyme. In unstimulated astrocytes, p29 resides in the perinuclear space. Cyclic AMP stimulation leads to the translocation of p29 to the plasma membrane coincident with the appearance of deiodinating activity. These data show that cAMP-dependent activation of type II iodothyronine 5'-deiodinase activity results from the synthesis of additional activating factor(s) that associates with inactive enzyme and leads to the translocation of enzyme polypeptide(s) from the perinuclear space to the plasma membrane.
dc.language.isoen_US
dc.relation<p><a href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&list_uids=8663169&dopt=Abstract">Link to Article in PubMed</a></p>
dc.relation.urlhttps://doi.org/10.1074/jbc.271.27.16363
dc.subjectAffinity Labels
dc.subjectAnimals
dc.subjectAnimals, Newborn
dc.subjectAstrocytes
dc.subjectBinding Sites
dc.subjectBrain
dc.subjectBucladesine
dc.subjectCatalysis
dc.subjectCells, Cultured
dc.subjectChromatography, Gel
dc.subjectCyclic AMP
dc.subjectEndocytosis
dc.subjectEnzyme Activation
dc.subjectImmunohistochemistry
dc.subjectIodide Peroxidase
dc.subjectIsoenzymes
dc.subjectKinetics
dc.subjectMacromolecular Substances
dc.subjectRats
dc.subjectThyroxine
dc.subjectLife Sciences
dc.subjectMedicine and Health Sciences
dc.titleCatalytic activity of type II iodothyronine 5'-deiodinase polypeptide is dependent upon a cyclic AMP activation factor
dc.typeJournal Article
dc.source.journaltitleThe Journal of biological chemistry
dc.source.volume271
dc.source.issue27
dc.identifier.legacycoverpagehttps://escholarship.umassmed.edu/oapubs/797
dc.identifier.contextkey579682
html.description.abstract<p>Type II iodothyronine 5'-deiodinase is an approximately 200-kDa multimeric enzyme in the brain that catalyzes the deiodination of thyroxine (T4) to its active metabolite, 3,5,3'-triiodothyronine. In astrocytes, cAMP stimulation is required to express catalytically active type II iodothyronine 5'-deiodinase. The affinity ligand N-bromoacetyl-L-T4 specifically labels the 29-kDa substrate-binding subunit (p29) of this enzyme in cAMP-stimulated astrocytes. To determine the requirements for cAMP-induced activation of this enzyme, we optimized N-bromoacetyl-L-T4 labeling of p29 in astrocytes lacking type II iodothyronine 5'-deiodinase activity and examined the effects of cAMP on the hydrodynamic properties and subcellular location of the enzyme. We show that the p29 subunit is expressed in unstimulated astrocytes and requires 10-fold higher concentrations of N-bromoacetyl-L-T4 to achieve incorporation levels equal to those of p29 in cAMP-stimulated cells. Gel filtration showed that p29 was part of a multimeric membrane-associated complex in both cAMP-stimulated and unstimulated astrocytes and that cAMP stimulation led to an increase of approximately 60 kDa in the mass of the holoenzyme. In unstimulated astrocytes, p29 resides in the perinuclear space. Cyclic AMP stimulation leads to the translocation of p29 to the plasma membrane coincident with the appearance of deiodinating activity. These data show that cAMP-dependent activation of type II iodothyronine 5'-deiodinase activity results from the synthesis of additional activating factor(s) that associates with inactive enzyme and leads to the translocation of enzyme polypeptide(s) from the perinuclear space to the plasma membrane.</p>
dc.identifier.submissionpathoapubs/797
dc.contributor.departmentDepartment of Physiology
dc.contributor.departmentDepartment of Medicine, Department of Medicine, Division of Endocrinology & Metabolism
dc.contributor.departmentMolecular Endocrinology Laboratory
dc.source.pages16363-8


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