Functional Interactions of metalloprotein YbeY, involved in ribosomal metabolism, with the putative metal efflux protein YbeX

Abstract

YbeY is a putative ribosomal endoribonuclease which has been implicated, among other things, to be involved in quality control of 70S ribosomes, in 17S pre-rRNA maturation and in ribosomal degradation. However, controversy reigns over its mode of action, substrates, co-factors, and interaction partners. Proposed interactors of YbeY include ribosomal protein S11, Era, YbeZ, and SpoT. In many bacteria ybeY is located in the ybeZYX-Int operon, where ybeZ encodes a PhoH subfamily protein with NTP hydrolase domain and ybeX encodes a putative Cobalt/Magnesium efflux protein. Depletion of YbeY and YbeX have largely overlapping phenotypes, including accumulation of 17S pre-rRNA and an approximately 1 kb 16S rRNA cleavage product, sensitivity to heat shock, and to the protein synthesis inhibitors chloramphenicol and erythromycin. Overexpression of the YbeY partially rescues the some of the phenotypes of ΔybeX. Taken together our results indicate a functional interaction between ybeY and ybeX.