Abstract
The cytoplasmic tails of classical cadherins form a multiprotein cadherin–catenin complex (CCC) that constitutes the major structural unit of adherens junctions (AJs). The CCC in AJs forms junctional clusters, “E clusters,” driven by cis and trans interactions in the cadherin ectodomain and stabilized by α-catenin–actin interactions. Additional proteins are known to bind to the cytoplasmic region of the CCC. Here, we analyze how these CCC-associated proteins (CAPs) integrate into cadherin clusters and how they affect the clustering process. Using a cross-linking approach coupled with mass spectrometry, we found that the majority of CAPs, including the force-sensing protein vinculin, interact with CCCs outside of AJs. Accordingly, structural modeling shows that there is not enough space for CAPs the size of vinculin to integrate into E clusters. Using two CAPs, scribble and erbin, as examples, we provide evidence that these proteins form separate clusters, which we term “C clusters.” As proof of principle, we show, by using cadherin ectodomain monoclonal antibodies (mAbs), that mAb-bound E-cadherin forms separate clusters that undergo trans interactions. Taken together, our data suggest that, in addition to its role in cell–cell adhesion, CAP-driven CCC clustering serves to organize cytoplasmic proteins into distinct domains that may synchronize signaling networks of neighboring cells within tissues.
Original language | English (US) |
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Article number | e2105550118 |
Journal | Proceedings of the National Academy of Sciences of the United States of America |
Volume | 118 |
Issue number | 29 |
DOIs | |
State | Published - Jul 20 2021 |
Funding
ACKNOWLEDGMENTS. We thank Dr. B. Mitchell for valuable discussions and suggestions. Proteomics, sequencing, and flow cytometry were performed at the Northwestern University Proteomics Center of Excellence, Genetic and Flow Cytometry Facilities. The work was supported by NIH Grants AR44016 and AR057992 (to S.M.T.), NSF Grant MCB-1914542 (to B.H.), and NIH Grants R01GM118584 and R01MH114817 (to L.S.).
Keywords
- Cadherin | catenins | cadherin-associated proteins | adherens junctions | protein sorting
ASJC Scopus subject areas
- General