Structural and Biophysical Analysis of the CLCA1 VWA Domain Suggests Mode of TMEM16A Engagement

Kayla N. Berry, Tom J. Brett

Research output: Contribution to journalArticle

1 Scopus citations

Abstract

The secreted protein calcium-activated chloride channel regulator 1 (CLCA1) utilizes a von Willebrand factor type A (VWA) domain to bind to and potentiate the calcium-activated chloride channel TMEM16A. To gain insight into this unique potentiation mechanism, we determined the 2.0-Å crystal structure of human CLCA1 VWA bound to Ca2+. The structure reveals the metal-ion-dependent adhesion site (MIDAS) in a high-affinity “open” conformation, engaging in crystal contacts that likely mimic how CLCA1 engages TMEM16A. The CLCA1 VWA contains a disulfide bond between α3 and α4 in close proximity to the MIDAS that is invariant in the CLCA family and unique in VWA structures. Further biophysical studies indicate that CLCA1 VWA is preferably stabilized by Mg2+ over Ca2+ and that α6 atypically extends from the VWA core. Finally, an analysis of TMEM16A structures suggests residues likely to mediate interaction with CLCA1 VWA.

Original languageEnglish
Pages (from-to)1141-1151.e3
JournalCell Reports
Volume30
Issue number4
DOIs
StatePublished - Jan 28 2020

Keywords

  • CLCA
  • CLCA1
  • MIDAS
  • SAXS
  • TMEM16A
  • VWA
  • airway disease
  • calcium-activated chloride channel
  • calcium-activated chloride channel regulator
  • calcium-activated chloride channel regulator 1
  • crystal structure
  • cystic fibrosis
  • metal-ion-dependent adhesion site motif
  • small-angle X-ray scattering
  • von Willebrand factor A domain

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