Spatial patterning via PTP adhesive phosphatases

Signaling pathways to the genome are a common way by which cells communicate with each other and their environment, and are often kinases or phosphatases. Pattern formation is the differential spatial specification of gene activity necessary for multicellularity. It has been suspected that signaling pathways are crucial players in pattern formation in metazoans, but exactly how the patterns arise from the signaling systems has not been shown. The model discussed here is based on the protein tyrosine phosphatases, and it is shown how this important signaling system may straightforwardly produce patterns typical of early development. The protein tyrosine phosphatases have architectural characteristics basically different from those of the kinases, with the receptor tyrosine phosphatases displaying structural motifs of cell adhesion molecules. These membrane-spanning phosphatases then have a unique mission in cell growth, cell shape, and differentiation quite apart from that of the kinases. The complex intracellular biochemistry involved is modeled in the simplest way, with the intent that concepts be emphasized over biochemical detail. (C) 1999 Academic Press.