title: The Whereabouts of microRNA Actions: Cytoplasm and Beyond.
abstract: MicroRNAs (miRNAs) are a conserved class of approximately 22 nucleotide (nt) short noncoding RNAs that normally silence gene expression via translational repression and/or degradation of targeted mRNAs in plants and animals. Identifying the whereabouts of miRNAs potentially informs miRNA functions, some of which are perhaps specialized to specific cellular compartments. In this review, the significance of miRNA localizations in the cytoplasm, including those at RNA granules and endomembranes, and the export of miRNAs to extracellular space will be discussed. How miRNA localizations and functions are regulated by protein modifications on the core miRNA-binding protein Argonaute (AGO) during normal and stress conditions will be explored, and in conclusion new AGO partners, non-AGO miRNA-binding proteins, and the emergent understanding of miRNAs found in the nucleoplasm, nucleoli, and mitochondria will be discussed.
authors.affiliation: Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205, USA. Electronic address: anthony.leung@jhu.edu.
authors.forename: Anthony K L
authors.initials: AKL
authors.lastname: Leung
mesh_terms: D000818:Animals; D060565:Argonaute Proteins / Q000235:genetics*; D002467:Cell Nucleus / Q000235:genetics; D003593:Cytoplasm / Q000235:genetics; D005786:Gene Expression Regulation; D020868:Gene Silencing; D006801:Humans; D035683:MicroRNAs / Q000235:genetics*; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000235:genetics*
chemical_list: D060565:Argonaute Proteins; D035683:MicroRNAs; D012333:RNA, Messenger
keywords: Argonaute; circulating miRNAs; localization; miRNA; organelle; post-translational modification