FIG 1.

Mechanism of biofilm formation in P. fluorescens. (A) Overview of LapD- and LapG-mediated regulation of LapA localization to the outer membrane. Differential recruitment of LapG by LapD in response to cytoplasmic c-di-GMP levels controls LapA's surface attachment. When LapG is not sequestered to the inner membrane by LapD, LapG proteolytically cleaves the N terminus of LapA between two alanine residues of a TAAG motif, releasing the adhesin from the outer membrane, thus liberating the cell from the biofilm matrix. (B) Web Logo plot (24) of putative LapA-like substrates identified previously (4) reveals a series of conserved residues (green) upstream of the TAAG cleavage sequence (red).