Are cuproproteins part of the multi-protein framework for making the Casparian strip?

Casparian strip (CS) is a lignified structure localized on the cell wall between adjacent root endodermal cells and functions as an apoplastic diffusion barrier in the root. The polarly localized, lignin-based CS is an excellent system for studying peptide signaling and position recognition. In this short review, we summarize advances in the past decade on the molecular mechanism governing CS development. In addition to the multi-protein framework underlying the CS membrane domain, we discuss recently observed participation of cell wall located cuproproteins in CS formation. These new discoveries shed light on a potential CS wall domain that coordinates with the membrane domain to provide bidirectional positional information for guiding precise CS development.