Figure 7.

Proposed models for LPA signaling in tissue growth and patterning of the pLLP. (A) When Lpar2b is depleted, Lats1/2 is active and phosphorylates Yap1. P-Yap1 is retained in the cytoplasm and becomes inactive. Genes required for cell proliferation and organ growth is not expressed, resulting in a smaller pLLP size. As the Wnt domain (blue) remains constant, the FGF region (yellow) is thus more restricted to the posterior edge, which in turn reduces the number of rosettes that can be formed within the pLLP. (B) When Lpar2b is present in the pLLP, it's activated upon LPA binding, and presumably signals through its coupled G-proteins to inhibit Lats1/2 activity. Yap1 is thus not phosphorylated and translocates to the nucleus to activate gene transcription that promotes growth of the pLLP. The pLLP reaches its normal size, which provides enough space for FGF signaling and rosette formation.