Differential PaxillinB dynamics at Dictyostelium cell-substrate adhesions

Abstract

Adhesion-based migration is regulated by focal adhesions, multi-protein nanostructures linking the intracellular cytoskeleton to the extracellular substrate. Efficient adhesion-based migration has been shown to be regulated by focal adhesion dynamics such as lifetime, size and turnover, which in turn are influenced by the molecular composition of focal adhesions. We recently identified the formation of cell-substrate adhesion populations in Dictyostelium discoideum with differing molecular compositions, but it is unclear how these distinct compositions influence Dictyostelium adhesion dynamics and cell migration. Here, we further investigate the role of molecular composition on Dictyostelium adhesion lifetime and protein turnover during cell migration. We show that co-localization of VinculinB to PaxillinB-positive cell-substrate adhesions increases adhesion lifetime without changing PaxillinB turnover. We further show that perturbing cell-substrate adhesion composition with a PaxillinB N-terminal truncation increases adhesion lifetime and decreases PaxillinB turnover at adhesions. These findings suggest that similar to mammalian focal adhesions, molecular composition of Dictyostelium cell-substrate adhesion regulates their adhesion lifetimes and protein turnover, providing insight into how cell-substate adhesions function during Dictyostelium cell migration. SUMMARY STATEMENTFierro Morales and Roh-Johnson demonstrate that Dictyostelium PaxillinB, a homolog of the core focal adhesion protein Paxillin, exhibits differential dynamics in distinct populations of cell-substrate adhesions.