HuR stabilizes vacuolar H+-translocating ATPase mRNA during cellular energy depletion.
V-ATPases are multisubunit membrane proteins that use ATP binding and hydrolysis to transport protons across membranes against a concentration gradient. Although some cell types express plasma membrane forms of these transporters, all eukaryotes require V-ATPases to maintain an acidic pH in membrane-bound compartments of endocytic and secretory networks to facilitate protein trafficking and processing. Mammalian cells that completely lack V-ATPases are not viable; yet, the abundance of V-ATPases can differ among cell types by an order of magnitude or more, requiring precise control of their expression. We previously showed that mRNA stability appears to play a major role in regulating overall abundance of V-ATPases. In this report, we demonstrate that the stability of V-ATPase mRNA is regulated through AU-rich elements in 3'-untranslated regions. Unlike some mRNAs that are short-lived due to the presence of these elements, V-ATPase mRNAs have half-lives of hours to days. However, during stress induced by ATP depletion, AU-rich elements are necessary to maintain stability of these transcripts and their presence in the cytoplasm. HuR, an RNA-binding protein that interacts with and stabilizes AU-rich mRNAs, shows increased binding to some V-ATPase mRNAs during ATP depletion. siRNA-mediated knockdown of HuR results in diminished V-ATPase expression. These results indicate that AU-rich elements and associated proteins can play a role in regulation of even very stable mRNAs by protecting against loss during cellular stress.
Jeyaraj
Selvi
S
Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, 43210, USA.
Dakhlallah
Duaa
D
Hill
Stephanie R
SR
Lee
Beth S
BS
D020856:AT Rich Sequence / Q000235:genetics; D000255:Adenosine Triphosphate / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D000954:Antigens, Surface / Q000378:metabolism*; D002460:Cell Line; D051959:ELAV Proteins; D000067780:ELAV-Like Protein 1; D004734:Energy Metabolism; D006801:Humans; D034622:RNA Interference; D020871:RNA Stability; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000378:metabolism*; D025262:Vacuolar Proton-Translocating ATPases / Q000235:genetics* / Q000378:metabolism*
D000954:Antigens, Surface; D051959:ELAV Proteins; D000067780:ELAV-Like Protein 1; C098770:ELAVL1 protein, human; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D016601:RNA-Binding Proteins; D000255:Adenosine Triphosphate; C462522:ATP6V1E2 protein, human; D025262:Vacuolar Proton-Translocating ATPases