Download MendeleyThe Structure of the Plakin Domain of Plectin Reveals an Extended Rod-like Shape.
Ortega, E., Manso, J.A., Buey, R.M., Carballido, A.M., Carabias, A., Sonnenberg, A., de Pereda, J.M.(2016) J Biological Chem 291: 18643-18662
- PubMed: 27413182
- DOI: https://doi.org/10.1074/jbc.M116.732909
- Primary Citation of Related Structures:
5J1F, 5J1G, 5J1H, 5J1I - PubMed Abstract:
Plakins are large multi-domain proteins that interconnect cytoskeletal structures. Plectin is a prototypical plakin that tethers intermediate filaments to membrane-associated complexes. Most plakins contain a plakin domain formed by up to nine spectrin repeats (SR1-SR9) and an SH3 domain. The plakin domains of plectin and other plakins harbor binding sites for junctional proteins. We have combined x-ray crystallography with small angle x-ray scattering (SAXS) to elucidate the structure of the plakin domain of plectin, extending our previous analysis of the SR1 to SR5 region. Two crystal structures of the SR5-SR6 region allowed us to characterize its uniquely wide inter-repeat conformational variability. We also report the crystal structures of the SR7-SR8 region, refined to 1.8 Å, and the SR7-SR9 at lower resolution. The SR7-SR9 region, which is conserved in all other plakin domains, forms a rigid segment stabilized by uniquely extensive inter-repeat contacts mediated by unusually long helices in SR8 and SR9. Using SAXS we show that in solution the SR3-SR6 and SR7-SR9 regions are rod-like segments and that SR3-SR9 of plectin has an extended shape with a small central kink. Other plakins, such as bullous pemphigoid antigen 1 and microtubule and actin cross-linking factor 1, are likely to have similar extended plakin domains. In contrast, desmoplakin has a two-segment structure with a central flexible hinge. The continuous versus segmented structures of the plakin domains of plectin and desmoplakin give insight into how different plakins might respond to tension and transmit mechanical signals.
- From the Instituto de Biología Molecular y Celular del Cancer, Consejo Superior de Investigaciones Científicas, University of Salamanca, 37007 Salamanca, Spain.
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