Structure prediction of homo-oligomer complex of angulin proteins, LSR, ILDR1, and ILDR2, at tricellular tight junction

Abstract

Angulin proteins (LSR, ILDR1, ILDR2) are transmembrane proteins which contribute to form tight junctions at epithelial tricellular junctions. This mechanism is known to play a key role in controlling macromolecule flux across cell layers by blocking tricellular tube. Despite its great importance, however, little has been known about how angulin protein can be localized specifically at tricellular cell corners. Based on various known experimental data so far, we hypothesize that ig-like domain, which is extracellular region of angulin protein, plays a key role in localization and propose homo-trimeric structure of ig-like domains. For this purpose, we first predict the structure of ig-like domain of each angulin protein by comparative modeling method. We then apply symmetric monomer docking method to construct various forms of trimer model candidates. Lastly, filtering and scoring to assess those candidate models are applied so that we can propose a few plausible structural models for the trimer of angulin proteins.