cells secrete CfaD, a protein that is similar to cathepsin proteases. starving cells, as indicated by a high concentration of CMF (Jain et al., 1992; Yuen et al., 1995), the cells aggregate using relayed pulses of extracellular cAMP as a chemoattractant (Aubry and Firtel, 1999). The aggregating cells form streams that break up into groups… Continue reading cells secrete CfaD, a protein that is similar to cathepsin proteases.