Functional modules of human RNase P. Human RNase P has 10 protein subunits that associate with H1 RNA. A new functional arrangement of these protein subunits in the ribonucleoprotein complex is shown. The approximate positions of the subunits are based on the solved Cryo-EM structure of human RNase P. Traditionally, RNase P RNA is divided into two functional units, the specificity domain and catalytic domain, which refer to binding and cleavage of precursor tRNA by bacterial RNase P. However, following new roles of human RNase P and its subunits in myriad biological processes, other than 5′ end cleavage of precursor tRNA (see text), a new rough arrangement of the subunits in defined functional modules is represented. The functional domains cover transcription, chromatin remodeling, innate immunity, DNA damage repair, and ribonuclease module. Since molecular processes are interconnected, such as chromatin remodeling and transcription, the cooperation of these conjoining domains and sharing of subunits is expected. The Alba-like domain is composed of Rpp20 and Rpp25 and shared by RNase MRP and MRP-TERT. In yeast, the homologs of these two proteins are shared by the telomerase (Lemieux et al. 2016; Garcia et al. 2020).
