Phosphorylation of the human microRNA-generating complex mediates MAPK/Erk signaling.
MicroRNAs (miRNAs) govern an expanding number of biological and disease processes. Understanding the mechanisms by which the miRNA pathway is regulated, therefore, represents an important area of investigation. We determined that the human miRNA-generating complex is comprised of Dicer and phospho-TRBP isoforms. Phosphorylation of TRBP is mediated by the mitogen-activated protein kinase (MAPK) Erk. Expression of phospho-mimic TRBP and TRBP phosphorylation enhanced miRNA production by increasing stability of the miRNA-generating complex. Mitogenic signaling in response to serum and the tumor promoter PMA was dependent on TRBP phosphorylation. These effects were accompanied by a coordinated increase in levels of growth-promoting miRNA and reduced expression of let-7 tumor suppressor miRNA. Conversely, pharmacological inhibition of MAPK/Erk resulted in an anti-growth miRNA profile. Taken together, these studies indicate that the MAPK/Erk pathway regulates the miRNA machinery and suggest a general principle, wherein signaling systems target the miRNA pathway to achieve biological responses.
Paroo
Zain
Z
Department of Biochemistry, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA.
Ye
Xuecheng
X
Chen
She
S
Liu
Qinghua
Q
D005786:Gene Expression Regulation; D006367:HeLa Cells; D006801:Humans; D020935:MAP Kinase Signaling System; D035683:MicroRNAs / Q000378:metabolism*; D010766:Phosphorylation; D020033:Protein Isoforms / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000378:metabolism; D043244:Ribonuclease III / Q000378:metabolism; D000099253:Trans-Activation Responsive RNA-Binding Protein
D035683:MicroRNAs; D020033:Protein Isoforms; D016601:RNA-Binding Proteins; D043244:Ribonuclease III; D000099253:Trans-Activation Responsive RNA-Binding Protein