Figure 1.

Clavata pathway model. The receptor-like kinase protein, CLV1, and the receptor-like protein, CLV2, are localized to the plasma membrane. The putative ligand, CLV3 is produced as a propeptide and then cleaved to release the mature signaling molecule. Upon activation, the CLV1/2 complex blocks the activity of the PP2C proteins, POL and PLL1 via an unknown mechanism. When CLV3 is not present, POL and PLL1 are active and through unidentified signaling intermediates upregulate the homeodomain transcription factor, WUS, which is required for the maintenance and specification of the stem cells.