Might modulate either transcription and/or translation. Required for dimerization of active 70S ribosomes into 100S ribosomes in stationary phase; 100S ribosomes are translationally inactive and sometimes present during exponential growth. Interacts with 100S ribosomes. Is repressed by light, since the transcript is synthesized in the dark, but upon 20 minutes of illumination, transcript levels fall below detectable limits. This light-repressed transcript is present only in dark-adapted cells. Is rapidly translated at the onset of illumination; in fact, is one of the first proteins to be synthesized upon illumination of dark-adapted cells. Repression of the transcript in the light requires protein synthesis, which suggests that a specific protein is directly involved in lrtA light repression. Knockout mutants grown in continuous light appear to be the same as wild-type, showing no differences in growth or photosynthetic activity. The transcript for lrtA is more stable in the dark than in the light: a 3-hour half-life is estimated in the dark, whereas a 4-minute half-life is observed in the light. Belongs to the HPF/YfiA ribosome-associated protein family. Long HPF subfamily.