The ability to sense mechanical forces is vital to cell physiology. Yet, the 
molecular basis of mechano-signaling remains unclear. Previous studies have 
shown that zyxin, a focal adhesion protein, is recruited at force-bearing sites 
on the actin cytoskeleton and, therefore, identifying zyxin as a mechano-sensing 
protein candidate. Furthermore, zyxin accumulation at force-bearing sites 
requires the LIM domain located at the C-terminus of zyxin. The zyxin LIM domain 
consists of three LIM motifs, each containing two zinc-binding sites. Since 
individual LIM motifs do not accumulate at focal adhesions or force-bearing 
sites, we hypothesize that multiple zyxin LIM domains increase force 
sensitivity. Using a miniature force sensor and GFP-tagged LIM variants, we 
quantified the relationship between single, tandem dimer and trimer LIM protein 
localization and traction forces. While the presence of extra LIM domains 
affected VASP recruitment to focal adhesions, force sensitivity was not enhanced 
over the single LIM domain. Therefore, zyxin force sensitivity is optimal with a 
single LIM domain, while additional LIM domains fail to enhance force 
sensitivity.