"[InterPro-based annotation correctly captures the phosphorelay sensor kinase and general signal transduction functions inferred from the hybrid histidine kinase architecture.]"

"[TreeGrafter assigned a hyperosmotic-response term, but that specific process is not directly supported by KT2440 experimental evidence located for retS.]"

"[Automated methods recover protein histidine kinase activity for the RetS-family hybrid sensor kinase.]"

"The three genes were significantly upregulated in the retS mutant, with fold-changes >3 for hcp1 and >1.5 for tssB1 and PP3104"

"This effect was not observed in the stationary phase (Fig. 4b), which suggests that repression of the K1-T6SS by RetS occurs mainly during exponential growth."

"This indicates that GacS is a positive regulator of K1-T6SS expression, and this activity is repressed only by RetS in the exponential phase of growth."

"RecName: Full=histidine kinase"

"[923 aa membrane histidine kinase with] DOMAIN 404..624 Histidine kinase [...] DOMAIN 642..764 Response regulatory [...] DOMAIN 791..910 Response regulatory [, i.e. a HisKA kinase module plus two receiver domains, with multiple TRANSMEM helices.]"

"PP_4824 is a RetS-family hybrid sensor kinase with 7TMR-DISM, HisKA, and two receiver domains."

"Direct KT2440 literature supports repression of K1-T6SS expression by RetS during exponential growth."

"RetS represses transcription of the K1 type VI secretion system"

"PP_4824 functions primarily as an **upstream negative regulator of K1‑T6SS transcription**, acting most strongly under conditions where KT2440 would otherwise allocate resources to growth"

"K1‑T6SS expression is **positively regulated by GacS–GacA** and **repressed by RetS**, which inhibits this TCS"

"RetS is described as an “orphan” or “hybrid” sensor kinase that modulates the GacS/GacA pathway in *Pseudomonas*, often functioning as an upstream antagonist of the Gac/Rsm cascade."

"RetS-family proteins are described as **inner-membrane sensor kinases** with **periplasmic sensory modules** and **cytoplasmic kinase/receiver modules**"

"**cytosolic histidine kinase (HisKA-type) region** plus **tandem receiver (REC/RR) domains**"

"negatively regulates the GacS–GacA-controlled transcriptional program for the K1 type VI secretion system"

"RetS inhibits GacS signaling via **direct interactions between the HK regions**"