FAF is a family of plant proteins that regulate the size of the shoot meristem by modulating the CLV3-WUS feedback loop. The proteins are expressed in the centre of the shoot meristem, overlapping with the site of WUS - the homeodomain transcription factor WUSCHEL- expression. FAF proteins are capable of modulating shoot growth by repressing WUS in the organising centre of the shoot meristem. The ability of plants to form new organs throughout their life cycle requires tight control of the meristems to avoid unregulated growth. Plants have evolved an elaborate genetic network that controls meristem size and maintenance. WUS and the CLAVATA (CLV) ligand-receptor system are at the core of the network that regulates the size of the stem cell population in the shoot meristem.