FN1 and polycystic kidney disease: Furthermore, this cluster contained multiple proteins with a polycystic kidney disease (PKD) domain, which are mainly found in large extracellular cell surface glycoproteins (IPR000601), multiple proteins with a fibronectin domain that is among others involved in protein binding and cell adhesion (IPR003961), and multiple proteins annotated as outer cell wall protein that shared sequence homology (32%–33%) with proteins from the Bacillota phylum containing an S‐layer homology domain.