Figure 1.

Regulation of microRNA (miRNA) function by modulating its biogenesis and targeting in the immune system. Immune cells orchestrate miRNA function through regulating or modifying the key enzymes and proteins involved in miRNA biogenesis, such as Exportin 5, Dicer, Ago2, and some RNA binding proteins (RBPs). Moreover, miRNAs may selectively target mRNAs according to the miRNA site types in distinct immune cells. miRNA-mediated targeting may also be regulated by competing endogenous RNA (ceRNAs) or affected by alternative poly(A) site usage in immune responses. The events in the miRNA biogenesis and targeting pathways that are able to be regulated during immune responses are summarized in the boxes outlined with dash lines and numbered according to the text. The arrows with solid lines indicate each step in the process of miRNA biogenesis, while the arrows with dash lines indicate how that step is modulated in immune cells.