We have shown that interaction of the commensal oral bacterium Streptococcus gordonii with salivary mucins results in presentation of new adhesins on the bacterial surface that enhance mucin-binding, thus ensuring its persistence in the oral cavity. We are using proteomic and transcriptomic approaches to identify the mechanisms by which these bacteria “sense” their surroundings and transduce the signal intracellularly allowing them to adjust their expression of adhesins.