Endoribonuclease that plays a central role in RNA processing and decay. Required for the maturation of 5S and 16S rRNAs and the majority of tRNAs. Also involved in the degradation of most mRNAs (By similarity). Endonucleolytic cleavage of single-stranded RNA in A- and U-rich regions. Binds 1 Mg(2+) ion per subunit. Component of the RNA degradosome, which is a multiprotein complex involved in RNA processing and mRNA degradation. Within the RNA degradosome, RNase E assembles into a homotetramer formed by a dimer of dimers (By similarity). Belongs to the RNase E/G family. RNase E subfamily. This sequence is much shorter than orthologs.