5H5M

Crystal structure of HMP-1 M domain

Summary for 5H5M

• Entry DOI: 10.2210/pdb5h5m/pdb
• Descriptor: Alpha-catenin-like protein hmp-1 (2 entities in total)
• Functional Keywords: alpha-catenin, four helix bundle, cell adhesion
• Biological source: Caenorhabditis elegans
• Cellular location: Cell junction, adherens junction : P90947
• Total number of polymer chains: 2
• Total formula weight: 85715.75

Authors

Kang, H.,Bang, I.,Weis, W.I.,Choi, H.J. (deposition date: 2016-11-08, release date: 2017-03-29, Last modification date: 2024-05-29)

Primary citation

Kang, H.,Bang, I.,Jin, K.S.,Lee, B.,Lee, J.,Shao, X.,Heier, J.A.,Kwiatkowski, A.V.,Nelson, W.J.,Hardin, J.,Weis, W.I.,Choi, H.J.
Structural and functional characterization of Caenorhabditis elegans alpha-catenin reveals constitutive binding to beta-catenin and F-actin
J. Biol. Chem., 292:7077-7086, 2017

PubMed Abstract: Intercellular epithelial junctions formed by classical cadherins, β-catenin, and the actin-binding protein α-catenin link the actin cytoskeletons of adjacent cells into a structural continuum. These assemblies transmit forces through the tissue and respond to intracellular and extracellular signals. However, the mechanisms of junctional assembly and regulation are poorly understood. Studies of cadherin-catenin assembly in a number of metazoans have revealed both similarities and unexpected differences in the biochemical properties of the cadherin·catenin complex that likely reflect the developmental and environmental requirements of different tissues and organisms. Here, we report the structural and biochemical characterization of HMP-1, the α-catenin homolog, and compare it with mammalian α-catenin. HMP-1 shares overall similarity in structure and actin-binding properties, but displayed differences in conformational flexibility and allosteric regulation from mammalian α-catenin. HMP-1 bound filamentous actin with an affinity in the single micromolar range, even when complexed with the β-catenin homolog HMP-2 or when present in a complex of HMP-2 and the cadherin homolog HMR-1, indicating that HMP-1 binding to F-actin is not allosterically regulated by the HMP-2·HMR-1 complex. The middle ( M) domain of HMP-1 appeared to be less conformationally flexible than mammalian α-catenin, which may underlie the dampened effect of HMP-2 binding on HMP-1 actin-binding activity compared with that of the mammalian homolog. In conclusion, our data indicate that HMP-1 constitutively binds β-catenin and F-actin, and although the overall structure and function of HMP-1 and related α-catenins are similar, the vertebrate proteins appear to be under more complex conformational regulation.

PubMed: 28298447
DOI: 10.1074/jbc.M116.769778

Experimental method

X-RAY DIFFRACTION (2.4 Å)