title: Proteomic characterization of messenger ribonucleoprotein complexes bound to nontranslated or translated poly(A) mRNAs in the rat cerebral cortex.
abstract: Receptor-triggered control of local postsynaptic protein synthesis plays a crucial role for enabling long lasting changes in synaptic functions, but signaling pathways that link receptor stimulation with translational control remain poorly known. Among the putative regulatory factors are mRNA-binding proteins (messenger ribonucleoprotein, mRNP), which control the fate of cytosolic localized mRNAs. Based on the assumption that a subset of mRNA is maintained in an inactive state, mRNP-mRNA complexes were separated into polysome-bound (translated) and polysome-free (nontranslated) fractions by sucrose density centrifugation. Poly(A) mRNA-mRNP complexes were purified from a postmitochondrial extract of rat cerebral cortex by oligo(dT)-cellulose affinity chromatography. The mRNA processing proteins were characterized, from solution, by a nanoflow reverse phase-high pressure liquid chromatography-mu-electrospray ionization mass spectrometry. The majority of detected mRNA-binding proteins was found in both fractions. However, a small number of proteins appeared to be fraction-specific. This subset of proteins is by far the most interesting because the proteins are potentially involved in controlling an activity-dependent onset of translation. They include transducer proteins, kinases, and anchor proteins. This study of the mRNP proteome is the first step in allowing future experimentation to characterize individual proteins responsible for mRNA processing and translation in dendrites.
authors.affiliation: Beckman Institute/Neuronal Pattern Analysis, University of Illinois, Urbana, Illinois 61801, USA. angenstein@ifn-magdeburg.de
authors.forename: Frank
authors.initials: F
authors.lastname: Angenstein
authors.forename: Anne M
authors.initials: AM
authors.lastname: Evans
authors.forename: Shuo-Chien
authors.initials: SC
authors.lastname: Ling
authors.forename: Robert E
authors.initials: RE
authors.lastname: Settlage
authors.forename: Scott
authors.initials: S
authors.lastname: Ficarro
authors.forename: Franklin A
authors.initials: FA
authors.lastname: Carrero-Martinez
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Shabanowitz
authors.forename: Donald F
authors.initials: DF
authors.lastname: Hunt
authors.forename: William T
authors.initials: WT
authors.lastname: Greenough
mesh_terms: D000818:Animals; D002458:Cell Fractionation; D002499:Centrifugation, Density Gradient; D002540:Cerebral Cortex; D002846:Chromatography, Affinity; D002851:Chromatography, High Pressure Liquid; D046911:Macromolecular Substances; D011132:Polyribosomes / Q000378:metabolism; D011485:Protein Binding; D014176:Protein Biosynthesis; D040901:Proteomics; D012333:RNA, Messenger / Q000302:isolation & purification / Q000378:metabolism*; D051381:Rats; D020318:Rats, Long-Evans; D012261:Ribonucleoproteins / Q000032:analysis / Q000302:isolation & purification* / Q000378:metabolism; D012270:Ribosomes / Q000378:metabolism; D021241:Spectrometry, Mass, Electrospray Ionization
chemical_list: D046911:Macromolecular Substances; D012333:RNA, Messenger; D012261:Ribonucleoproteins; C026452:messenger ribonucleoprotein