Stormorken syndrome is a multiorgan hereditary disease caused by dysfunction of the endoplasmic reticulum (ER) Ca2+ sensor protein STIM1, which forms the Ca2+ release-activated Ca2+ (CRAC) channel together with the plasma membrane channel Orai1. ER Ca2+ store depletion activates STIM1 by releasing the intramolecular "clamp" formed between the coiled coil 1 (CC1) and CC3 domains of the protein, enabling the C terminus to extend and interact with Orai1. The most frequently occurring mutation in patients with Stormorken syndrome is R304W, which destabilizes and extends the STIM1 C terminus independently of ER Ca2+ store depletion, causing constitutive binding to Orai1 and CRAC channel activation. We found that in cis deletion of one amino acid residue, Glu296 (which we called E296del) reversed the pathological effects of R304W. Homozygous Stim1 E296del+R304W mice were viable and phenotypically indistinguishable from wild-type mice. NMR spectroscopy, molecular dynamics simulations, and cellular experiments revealed that although the R304W mutation prevented CC1 from interacting with CC3, the additional deletion of Glu296 opposed this effect by enabling CC1-CC3 binding and restoring the CC domain interactions within STIM1 that are critical for proper CRAC channel function. Our results provide insight into the activation mechanism of STIM1 by clarifying the molecular basis of mutation-elicited protein dysfunction and pathophysiology.

• MeSH
• aminokyseliny metabolismus   MeSH
• endoplazmatické retikulum metabolismus   MeSH
• kanály aktivované uvolněním vápníku * genetika   MeSH
• membránové proteiny * metabolismus   MeSH
• mutace MeSH
• myši MeSH
• protein ORAI1 metabolismus   MeSH
• protein STIM1 genetika   MeSH
• vápník metabolismus   MeSH
• vápníkové kanály metabolismus   MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

The calcium release activated calcium channel is activated by the endoplasmic reticulum-resident calcium sensor protein STIM1. On activation, STIM1 C terminus changes from an inactive, tight to an active, extended conformation. A coiled-coil clamp involving the CC1 and CC3 domains is essential in controlling STIM1 activation, with CC1 as the key entity. The nuclear magnetic resonance-derived solution structure of the CC1 domain represents a three-helix bundle stabilized by interhelical contacts, which are absent in the Stormorken disease-related STIM1 R304W mutant. Two interhelical sites between the CC1α1 and CC1α2 helices are key in controlling STIM1 activation, affecting the balance between tight and extended conformations. Nuclear magnetic resonance-directed mutations within these interhelical interactions restore the physiological, store-dependent activation behavior of the gain-of-function STIM1 R304W mutant. This study reveals the functional impact of interhelical interactions within the CC1 domain for modifying the CC1-CC3 clamp strength to control the activation of STIM1.

• MeSH
• abnormální erytrocyty MeSH
• dyslexie genetika   MeSH
• HEK293 buňky MeSH
• ichtyóza genetika   MeSH
• kanály aktivované uvolněním vápníku metabolismus   MeSH
• klonování DNA MeSH
• konformace nukleové kyseliny MeSH
• lidé MeSH
• magnetická rezonanční spektroskopie MeSH
• metoda terčíkového zámku MeSH
• migréna genetika   MeSH
• mióza genetika   MeSH
• molekulární modely MeSH
• mutace genetika   MeSH
• nádorové proteiny genetika   MeSH
• protein ORAI1 genetika   MeSH
• protein STIM1 genetika   MeSH
• slezina abnormality   MeSH
• svalová únava genetika   MeSH
• trombocytopatie genetika   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH