Meeting Abstract
Embryonic cells use adhesion to interpret microenvironmental cues, forming signaling compartments along adherent membranes that influence cell survival and developmental patterning. While it is known that dividing cells detach from the surrounding extracellular matrix and initiate extensive membrane remodeling, the in vivo impact of mitosis on adhesion-dependent signaling remains poorly characterized Here we show that mitotic membrane dynamics orchestrate adhesion-dependent signal polarization. We investigate in vivo signaling dynamics using the invertebrate chordate, Ciona intestinalis. In Ciona, matrix adhesion polarizes Fibroblast Growth Factor (FGF)-dependent induction of the heart progenitor lineage. Through targeted disruption and selective rescue of matrix adhesion in the heart progenitor lineage, we show that adhesion promotes localized enrichment of FGF receptors by inhibiting mitotic internalization and degradation. We have experimentally defined the integrin motif responsible for adhesion dependent retention of FGF receptors. Furthermore, our results indicate that adhesion polarizes receptor retention by influencing mitotic distribution of Caveolin-rich membrane domains. These results fundamentally re-define the relationship between cell division and adhesive signaling, revealing how mitotic membrane turnover resets historic, pre-mitotic receptor distribution according to contemporaneous adhesive cues.
