Part of the processive rRNA transcription and antitermination complex (rrnTAC). The complex forms an RNA-chaperone ring around the RNA exit tunnel of RNA polymerase (RNAP). It supports rapid transcription and antitermination of rRNA operons, cotranscriptional rRNA folding, and annealing of distal rRNA regions to allow correct ribosome biogenesis. This subunit may play a central role in organizing the structure. A ribosome-associated protein, deletion of which alters the expression of 494 genes, suggesting a role in global gene regulation (PubMed:26179141). Involved in control of pathogenesis-related genes. Required for the activation of virulence factors associated with acute infections (type 3 secretion system, T3SS) while suppressing virulence factors associated with chronic infections (biofilm formation and type 6 secretion system, T6SS). It probably acts at a post-transcriptional level (PubMed:24169572). a myo-inositol phosphate + H2O = myo-inositol + phosphate Homodimer. The rRNA transcription and antitermination complex (rrnTAC) consists of RNA polymerase (RNAP), NusA, NusB, NusE (rpsJ), NusG, SubB, ribosomal protein S4, DNA and precursor rRNA; S4 is more flexible than other subunits (By similarity). Interacts with the ribosome and with RNA polymerase (PubMed:26179141). Transcription is strongly induced during mouse infection. Decreased expression of T3SS genes and effectors. Loss of cytoxicity against human lung cell line A549, avirulent in a mouse infection model. Down-regulation of flagellar genes and up-regulation of T6SS structural genes and effectors, increased biofilm formation (PubMed:24169572). Grows less quickly at 37 degrees Celsius. Decreased susceptibility to antibiotics neomycin, streptomycin, gentamycin, spectinomycin, ciprofloxacin and ofloxacin. Increased ribosome stalling on leader peptide PA5471.1 mRNA, leads to increased expression of PA5471 and up-regulation of the MexXY efflux system (PubMed:26179141). Belongs to the inositol monophosphatase superfamily.