Structure of an L27 Domain Heterotrimer from Cell Polarity Complex Patj/Pals1/Mals2 Reveals Mutually Independent L27 Domain Assembly Mode

Background: Tandem L27 domains are important for multidomain proteins to assemble into supramolecular complexes for cell polarity regulation. Results: Tandem L27 domain-mediated tripartite Patj/Pals1/Mals2 and DLG1 CASK/Mals2 complexes form in a mutually independent assembly mode. Conclusion: The mutually independent assembly mode may be a novel mechanism for tandem L27 domain-mediated, tripartite complex formation. Significance: These findings reveal the distinct mechanism of tandem L27 domain-mediated assembly of obligate supramolecular complexes.