Signaling Cell Fate in Plant Meristems Richard Waites, Rüdiger Simon  Cell  Volume 103, Issue 6, Pages 835-838 (December 2000) DOI: 10.1016/S0092-8674(00)00186-0

Figure 1 Meristem Organization and Regulation of Stem Cell Number (A) Sectional view of the layered structure of a wild-type shoot meristem. The boxed area encloses the central zone with CLV3 expressing stem cells (red). (B) Close-up view of a wild-type shoot meristem. WUS expression (green) promotes stem cell fate in overlying cells. Expression of CLV3 in stem cells activates a restrictive signal transduction pathway that represses WUS activity. (C) In clv mutants, the restrictive pathway fails, and stem cells accumulate. (D) wus mutants are unable to maintain stem cells, and expression of the stem cell marker CLV3 is reduced. Cell 2000 103, 835-838DOI: (10.1016/S0092-8674(00)00186-0)

Figure 2 The CLAVATA Signaling Complex The leucine-rich repeat receptor kinase CLV1 forms a plasma membrane heterodimeric receptor with CLV2 (left part), held together by disulfide bridges. Binding of CLV3 (and a helper protein?) induces the assembly of a high molecular weight signaling complex (right part), comprising also a phosphatase (KAPP) and a GTPase (ROP). The activated complex signals to the nucleus, possibly via MAP kinases, and restricts WUS expression. Cell 2000 103, 835-838DOI: (10.1016/S0092-8674(00)00186-0)