Has probably an essential function in the transcriptional regulation of the kdpFABCQ operon. Up-regulated in response to K(+) limitation (PubMed:18633573, PubMed:21947979). Induced under desiccating conditions (PubMed:23757278). kdpFABCQ deletion strains are only able to grow in the presence of K(+) concentrations above 60 uM. Belongs to the universal stress protein A family.