High affinity associations with α-SNAP enable calcium entry via Orai1 channels.
Molecular steps that activate store-operated calcium entry (SOCE) via Orai channel supramolecular complex remain incompletely defined. We have earlier shown that α-SNAP regulates the on-site functional assembly and calcium selectivity of Orai1 channels. Here we investigate the molecular basis of its...
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| Autores principales: | , , |
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| Formato: | article |
| Lenguaje: | EN |
| Publicado: |
Public Library of Science (PLoS)
2021
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| Materias: | |
| Acceso en línea: | https://doaj.org/article/9ea790ac24fe427a884293ec325154a3 |
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| Sumario: | Molecular steps that activate store-operated calcium entry (SOCE) via Orai channel supramolecular complex remain incompletely defined. We have earlier shown that α-SNAP regulates the on-site functional assembly and calcium selectivity of Orai1 channels. Here we investigate the molecular basis of its association with Orai, Stim and find that the affinity of α-SNAP for Orai and Stim is substantially higher than previously reported affinities between Stim and Orai sub-domains. α-SNAP binds the coiled-coil 3 (CC3) sub-domain of Stim1. Mutations of Tryptophan 430 in Stim1-CC3 disrupted α-SNAP association and SOCE, demonstrating a novel α-SNAP dependent function for this crucial subdomain. Further, α-SNAP binds the hinge region near the C-terminus of Orai1 and an additional broad region near the N-terminus and Valine 262 and Leucine 74 were necessary for these respective interactions, but not Orai, Stim co-clustering. Thus, high affinity interactions with α-SNAP are necessary for imparting functionality to Stim, Orai clusters and induction of SOCE. |
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