April 5, 2013

Cell adhesion is sticky business.  See what I did there?!  Comedy. Gold.  Seriously, though, cell adhesion is complicated, with many types of cell adhesion structures that form at specific regions of the cell at specific times.  As important as it is to understand cell adhesion and its role in development, cancer, and normal cell function, we are all thankful for papers like the one that today’s image comes from.

Cadherins are transmembrane proteins that form cell-cell adhesion structures called adherens junctions.  There are several types of adherens junctions, but they are all composed of clusters of cadherins whose extracellular domains interact with other cells’ cadherins and intracellular domains interact with the cell’s cytoskeleton.  Individual cadherin molecules provide negligible adhesive properties, so understanding how cadherin clusters form is an important question.   A recent paper delves into the details of this process, and finds that actin filaments are indeed necessary for cadherin cluster stability.  Hong and colleagues found that cadherin clusters that were uncoupled from actin were unstable and exhibited random mobility.  When the actin-binding domain of a cadherin-actin adaptor protein called α-catenin (domain called αABD) was coupled to these mutant cadherin structures, the adhesive clusters regained stability and deliberate mobility.  The images above show clusters of this αABD-cadherin chimera (left, green in merged) associated with actin filaments (middle, red in merged; arrows in inset point to colocalization).

Hong, S., Troyanovsky, R., & Troyanovsky, S. (2013). Binding to F-actin guides cadherin cluster assembly, stability, and movement originally published in the Journal of Cell Biology, 201 (1), 131-143 DOI: 10.1083/jcb.201211054