Classes of R proteins

• Class 1 Pto- Serine/Threonine Kinase

• Class 2 LRR-NBS-LZ/CC

• Class 3 LRR-NBS-TIR

• Class 4 Extracellular LRR (Cf genes)

• Class 5 Extracellular LRR- Serine thronine kinase

• As defined in Martin et al. Ann Rev Plant Biol 2003 54:23-61