Molecular Clustering of STIM1 with Orai1/CRACM1 at the Plasma Membrane Depends Dynamically on Depletion of Ca<sup>2+</sup> Stores and on Electrostatic Interactions

Calloway, Nathaniel; Vig, Monika; Kinét, Jean-Pierre; Holowka, David; Baird, Barbara

doi:10.1091/mbc.e07-11-1132

Cited by 139 publications

(154 citation statements)

References 41 publications

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“…We speculate that impaired translocation resulted from disrupted electrostatic interactions between the negative charges in this region and corresponding positive charges in the BmOrai1B C terminus. In support of this hypothesis, Calloway et al (45) reported that mutation of acidic residues in the cytoplasmic tail of Orai1 reduced STIM1 interactions, suggesting that electrostatic forces are involved in STIM1/Orai1 binding. In addition, we also showed that both the N and C termini of BmOrai1B are necessary for complete translocation of BmSTIM1 to the plasma membrane (Fig.…”

Section: Discussionmentioning

confidence: 90%

Bombyx mori Homologs of STIM1 and Orai1 Are Essential Components of the Signal Transduction Cascade That Regulates Sex Pheromone Production

Hull

Lee

Kajigaya

et al. 2009

Journal of Biological Chemistry

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Sex pheromone production in the pheromone gland (PG) of the silkmoth, Bombyx mori, is mediated by store-operated channels (SOCs) acting downstream of pheromone biosynthesis activating neuropeptide (PBAN) binding. Although recent studies have implicated STIM1 and Orai1 as essential components of SOCs, little is known about the molecular nature of the SOCs involved in sex pheromone production. In this study we cloned silkmoth homologs of STIM1 and Orai1 and sought to determine whether they comprise the PG SOC pathway. BmSTIM1 is expressed in multiple tissues and, in the PG, is encoded by two transcripts of differing size. BmOrai1A and BmOrai1B, which are identical except for a 37-residue N-terminal truncation in BmOrai1B, arise from alternative splicing of the bmorai1 locus and are expressed as independent transcripts in various tissues. In the PG, only BmOrai1B is actively transcribed. Fluorescent chimeras demonstrated that BmSTIM1 expression is restricted to the endoplasmic reticulum, whereas both BmOrai1A and BmOrai1B localize to the cell surface. In Ca 2؉ -free medium, thapsigargin-mediated depletion of endoplasmic reticulum Ca 2؉ stores resulted in redistribution of BmSTIM1 to the plasma membrane, but only when the BmOrai1 homologs were also overexpressed. Translocation was dependent on the BmSTIM1 C terminus "CRAC activation domain." Ala mutation of Lys 380 , Lys 383 , Lys 384 , Arg 382 , and Arg 385 suggests that translocation involves electrostatic interactions. Translocation was also seen following PBAN stimulation in cells co-expressing BmSTIM1, BmOrai1B, and the PBAN receptor. In vivo RNA interference-mediated knockdown of BmSTIM1 and BmOrai1 significantly reduced sex pheromone production without affecting cell viability.

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Section: Discussionmentioning

confidence: 90%

Bombyx mori Homologs of STIM1 and Orai1 Are Essential Components of the Signal Transduction Cascade That Regulates Sex Pheromone Production

Hull

Lee

Kajigaya

et al. 2009

Journal of Biological Chemistry

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“…We do not yet know whether the Orai-STIMct aggregates we observe are related to channel activation, or if they reflect the inactivation of channels that rapidly follows 2-APB-induced activation. Aggregation of Orai1 into m-sized clusters in the PM was recently reported to occur through altered electrostatic interactions of acidic residues in the Orai1 C terminus (33), possibly mediated by the STIMct. Whereas 2-APB causes a massive association between STIMct and Orai1, some constitutive association between STIMct and Orai1 can occur without 2-APB, a result agreeing with 3 recent reports in which STIM1ct was examined (24,30,34).…”

Section: Resultsmentioning

confidence: 99%

STIM protein coupling in the activation of Orai channels

Wang

Deng

Zhou

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

124

141

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STIM proteins are sensors of endoplasmic reticulum (ER) luminalCa 2؉ changes and rapidly translocate into near plasma membrane (PM) junctions to activate Ca 2؉ entry through the Orai family of highly Ca 2؉ -selective ''store-operated'' channels (SOCs). Dissecting the STIM-Orai coupling process is restricted by the abstruse nature of the ER-PM junctional domain. To overcome this problem, we studied coupling by using STIM chimera and cytoplasmic C-terminal domains of STIM1 and STIM2 (S1ct and S2ct) and identifying a fundamental action of the powerful SOC modifier, 2-aminoethoxydiphenyl borate (2-APB), the mechanism of which has eluded recent scrutiny. We reveal that 2-APB induces profound, rapid, and direct interactions between S1ct or S2ct and Orai1, effecting full Ca 2؉ release-activated Ca 2؉ (CRAC) current activation. The short 235-505 S1ct coiled-coil region was sufficient for functional Orai1 coupling. YFP-tagged S1ct or S2ct fragments cleared from the cytosol seconds after 2-APB addition, binding avidly to Orai1-CFP with a rapid increase in FRET and transiently increasing CRAC current 200-fold above basal levels. Functional S1ct-Orai1 coupling occurred in STIM1/STIM2 ؊/؊ DT40 chicken B cells, indicating ct fragments operate independently of native STIM proteins. The 2-APB-induced S1ct-Orai1 and S2-ct-Orai1 complexes undergo rapid reorganization into discrete colocalized PM clusters, which remain stable for >100 s, well beyond CRAC activation and subsequent deactivation. In addition to defining 2-APB's action, the locked STIMct-Orai complex provides a potentially useful probe to structurally examine coupling.calcium signaling ͉ DT40 cells ͉ CRAC channel A dynamic interplay between 2 membrane proteins, STIM and Orai, underlies an intricate coupling between Ca 2ϩ release from endoplasmic reticulum (ER) stores and Ca 2ϩ entry across the plasma membrane (PM) (1-3). The single spanning transmembrane proteins STIM1 and STIM2 function as sensors of ER luminal Ca 2ϩ changes (4-7). Depletion of luminal Ca 2ϩ within ER stores triggers STIM proteins to aggregate and undergo rapid translocation into closely juxtaposed ER-PM junctions to activate Ca 2ϩ entry through one or more of the 3-member family of PM tetra-spanning channel proteins, Orai1, Orai2, and Orai3 (8-10). The Orai proteins function as highly Ca 2ϩ -selective ''storeoperated'' channels (SOCs) (11,12). The activation of SOCs is crucial in mediating longer-term cytosolic Ca 2ϩ signals, replenishing intracellular stores, and homeostatic control of both cytosolic and ER luminal Ca 2ϩ levels (3,(11)(12)(13)(14). Orai1 coexpressed with STIM1 reconstitutes high levels of the inwardly-rectifying Ca 2ϩ release-activated Ca 2ϩ (CRAC) current (10, 15-17), the hallmark of SOCs (11,12).Despite close interactions (5, 18), the coupling mechanism between STIM and Orai proteins to activate Ca 2ϩ entry remains to be elucidated. Our approach was to examine the STIM-Orai interactions by using the reactive borate 2-aminoethoxydiphenyl borate (2-APB), a powerful modifier of SOC ...

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“…In particular, the model predicts that the helical stretch of basic residues (KIKKKR; Fig. 1 H, highlighted in purple) known to play a critical role in binding to Orai1 (Calloway et al, 2009(Calloway et al, , 2010Korzeniowski et al, 2010) is likely to be disrupted in STIM2β, whereas the regions responsible for STIM-STIM dimerization (Yang et al, 2012;Stathopulos et al, 2013) (Brandman et al, 2007). We applied thapsigargin (Tg) to deplete Ca 2+ stores and examine the effects of STIM2α and STIM2β on SOCE in HEK293 cells overexpressing Orai1 (Fig.…”

Section: Stim2β Is a Novel And Widely Expressed Stim2 Splice Isoformmentioning

confidence: 99%

Alternative splicing converts STIM2 from an activator to an inhibitor of store-operated calcium channels

Rana¹,

Yen²,

Sadaghiani³

et al. 2015

J Gen Physiol

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Molecular Clustering of STIM1 with Orai1/CRACM1 at the Plasma Membrane Depends Dynamically on Depletion of Ca²⁺ Stores and on Electrostatic Interactions

Cited by 139 publications

References 41 publications

Bombyx mori Homologs of STIM1 and Orai1 Are Essential Components of the Signal Transduction Cascade That Regulates Sex Pheromone Production

Bombyx mori Homologs of STIM1 and Orai1 Are Essential Components of the Signal Transduction Cascade That Regulates Sex Pheromone Production

STIM protein coupling in the activation of Orai channels

Alternative splicing converts STIM2 from an activator to an inhibitor of store-operated calcium channels

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Molecular Clustering of STIM1 with Orai1/CRACM1 at the Plasma Membrane Depends Dynamically on Depletion of Ca2+ Stores and on Electrostatic Interactions

Cited by 139 publications

References 41 publications

Bombyx mori Homologs of STIM1 and Orai1 Are Essential Components of the Signal Transduction Cascade That Regulates Sex Pheromone Production

Bombyx mori Homologs of STIM1 and Orai1 Are Essential Components of the Signal Transduction Cascade That Regulates Sex Pheromone Production

STIM protein coupling in the activation of Orai channels

Alternative splicing converts STIM2 from an activator to an inhibitor of store-operated calcium channels

Contact Info

Product

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Molecular Clustering of STIM1 with Orai1/CRACM1 at the Plasma Membrane Depends Dynamically on Depletion of Ca²⁺ Stores and on Electrostatic Interactions