PT  - JOURNAL ARTICLE
AU  - Yu Han
AU  - Annik Jakob
AU  - Sophia Engel
AU  - Annegret Wilde
AU  - Nils Schuergers
TI  - PATAN-domain response regulators interact with the Type IV pilus motor to control phototactic orientation in the cyanobacterium <em>Synechocystis</em> sp. PCC 6803
AID  - 10.1101/2021.06.11.447907
DP  - 2021 Jan 01
TA  - bioRxiv
PG  - 2021.06.11.447907
4099  - http://biorxiv.org/content/early/2021/06/11/2021.06.11.447907.short
4100  - http://biorxiv.org/content/early/2021/06/11/2021.06.11.447907.full
AB  - Many prokaryotes show complex behaviors that require the intricate spatial and temporal organization of cellular protein machineries, leading to asymmetrical protein distribution and cell polarity. One such behavior is cyanobacterial phototaxis which relies on the dynamic localization of the Type IV pilus motor proteins in response to light. In the cyanobacterium Synechocystis, various signaling systems encompassing chemotaxis-related CheY- and PatA-like response regulators are critical players in switching between positive and negative phototaxis depending on the light intensity and wavelength. In this study, we show that PatA-type regulators evolved from chemosensory systems. Using fluorescence microscopy and yeast-two-hybrid analysis, we demonstrate that they localize to the inner membrane, where they interact with the N-terminal cytoplasmic domain of PilC and the pilus assembly ATPase PilB1. By separately expressing the subdomains of the response regulator PixE, we confirm that only the N-terminal PATAN domain interacts with PilB1, localizes to the membrane, and is sufficient to reverse phototactic orientation. These experiments established that the PATAN domain is the principal output domain of PatA-type regulators which we presume to modulate pilus extension by binding to the pilus motor components.Competing Interest StatementThe authors have declared no competing interest.