Summarizing Signaling in Single-Celled Organisms

Summary

Yeasts and multicellular organisms have similar signaling mechanisms. Yeasts use cell-surface receptors and signaling cascades to communicate information on mating with other yeast cells. The signaling molecule secreted by yeasts is called mating factor.

Bacterial signaling is called quorum sensing. Bacteria secrete signaling molecules called autoinducers that are either small, hydrophobic molecules or peptide-based signals. The hydrophobic autoinducers, such as AHL, bind transcription factors and directly affect gene expression. The peptide-based molecules bind kinases and initiate signaling cascades in the cells.

Glossary

autoinducer

signaling molecule secreted by bacteria to communicate with other bacteria of its kind and others

mating factor

signaling molecule secreted by yeast cells to communicate to nearby yeast cells that they are available to mate and communicating their mating orientation

quorum sensing

method of cellular communication used by bacteria that informs them of the abundance of similar (or different) bacteria in the environment