Fig. 4.

Clp controls the expression of the HSAF biosynthesis operon by binding to c-di-GMP and responding to fatty-acid signals of LeDSF3 and spermidine. (A) Clp-dependent activation of HSAF biosynthesis operon expression at high cell density (high LeDSF3 level, panel a) or in the presence of cellular spermidine generated by a pathway described in the panel b. (B) Clp inhibits HSAF production by binding to c-di-GMP at low cell density (low LeDSF3 level, panel a) or decreasing the level of cellular spermidine by inactivating SpeD as described in the panel b. The details are described in context.