What do Dictyosteliumand mammary gland have in common?

Excerpt

The discoidin domain receptors, DDR1 and DDR2, display characteristics pertinent to the study of both extracellular matrix (ECM) and tyrosine-kinase-dependent intracellular signalling. DDR extracellular domains share homology with the Dictyostelium discoideumprotein discoidin, a lectin-like factor that is secreted by cells to form a primitive ECM during aggregation. In higher organisms, DDR1 and DDR2 function as receptors for collagen-rich substrates; ligation of collagens activates the tyrosine kinase domains intrinsic to the proteins. Thus DDRs mediate signalling events that are stimulated in response to cues from the ECM and are likely to be important determinants of cellular differentiation. This paper explores this hypothesis by examining the phenotypes of the DDR1-/- mouse. …