Five typical protein structures were recognised as involved in the resistance process or R genes: the TIR-NBS-LRR (TNLs), the CC-NBS-LRR (CNLs), the receptor-like kinase (RLKs), the receptor-like protein (RLPs) and the kinase-like protein.
LRR-RKs is a subfamily of the Receptor Kinase gene family (RLK).
The NBS-LRR gene family on the other hand is a separate family of R (resistance) genes which is further classified as toll/interleukin receptor (TIR)-NBS-LRR (TNL) or non-TNL/coiled coil-NBS-LRR (CNL).