The Wall Associated Kinases (WAKs) bind to both cross-linked polymers of pectin in the plant cell wall, but have a higher affinity for smaller fragmented pectins that are generated upon pathogen attack or wounding. WAKs are required for cell expansion during normal seedling development and this involves pectin binding and a signal transduction pathway involving MPK3 and invertase induction. Alternatively WAKs bind pathogen generated pectin fragments to activate a distinct MPK6 dependent stress response. Evidence is provided for a model for how newly generated pectin fragments compete for longer pectins to alter the WAK dependent responses.
Kohorn, Bruce D., "The state of cell wall pectin monitored by wall associated kinases: A model" (2015). Biology Faculty Publications. 162.