Fig. 6.

Working model of how luminal Lama5 regulates mammary epithelial growth and crosstalk. Schematic showing how the production of LMα5 by luminal MECs supports specifically the HR⁺ luminal cells, in which it enhances gene expression of ER, PR, Wnt4 and RANKL. The products of these genes then act on neighboring basal and HR⁻ epithelial cells to orchestrate epithelial growth and morphogenesis during puberty and pregnancy. Deficiency of LMα5 in the BM environment in turn leads to reduced gene expression in these genes, and defective intercellular communication and epithelial growth.