Orai1 and STIM1 proteins are the essential components of the Ca2+ release activated Ca2+ (CRAC) channel which is required for store-operated Ca2+ entry (SOCE) in T cells and subsequent signaling events leading to T cell activation, proliferation, and differentiation. Plasma membrane (PM)-localized Orai1 is the pore-forming subunit of the CRAC channel, and STIM1 is the Ca2+ sensor localized to the endoplasmic reticulum (ER) membrane in quiescent T cells. T cell receptor (TCR) stimulation leads to depletion of ER Ca2+ stores resulting in Ca2+ no longer being bound to STIM1. This activates STIM1 by triggering a lengthening conformational change which allows it to bind Orai1 at ER-PM junctions within the immunological synapse. Binding of STIM1 to Orai1 activates the CRAC channel resulting in SOCE. Although the functional importance of these events is well-known, the molecular mechanism supporting timely and efficient recruitment of both Orai1 and STIM1 to the ER-PM junctions remains poorly understood. We have found that, among several other TCR machinery proteins, both Orai1 and STIM1 are rapidly and transiently S-acylated upon TCR stimulation. Furthermore, using electrophysiology studies and Fura-2 Ca2+ imaging, we demonstrated that both Orai1 and STIM1 require S-acylation to form active CRAC channels and mediate SOCE. Lastly, our studies using total internal reflection fluorescence microscopy showed that a lack of S-acylation of either Orai1 or STIM1 resulted in significantly reduced Orai1/STIM1 colocalization as evident from the diminished PM puncta formation. These data describe a novel form of SOCE regulation in T cells that may provide new therapeutic avenues to treat diseases caused by dysfunctional CRAC channels, such as severe combined immunodeficiency and Störmorken syndrome.
","abstract_html":"<p>Orai1 and STIM1 proteins are the essential components of the Ca<sup>2+</sup> release activated Ca<sup>2+</sup> (CRAC) channel which is required for store-operated Ca<sup>2+</sup> entry (SOCE) in T cells and subsequent signaling events leading to T cell activation, proliferation, and differentiation. Plasma membrane (PM)-localized Orai1 is the pore-forming subunit of the CRAC channel, and STIM1 is the Ca<sup>2+</sup> sensor localized to the endoplasmic reticulum (ER) membrane in quiescent T cells. T cell receptor (TCR) stimulation leads to depletion of ER Ca<sup>2+</sup> stores resulting in Ca<sup>2+</sup> no longer being bound to STIM1. This activates STIM1 by triggering a lengthening conformational change which allows it to bind Orai1 at ER-PM junctions within the immunological synapse. Binding of STIM1 to Orai1 activates the CRAC channel resulting in SOCE. Although the functional importance of these events is well-known, the molecular mechanism supporting timely and efficient recruitment of both Orai1 and STIM1 to the ER-PM junctions remains poorly understood. We have found that, among several other TCR machinery proteins, both Orai1 and STIM1 are rapidly and transiently S-acylated upon TCR stimulation. Furthermore, using electrophysiology studies and Fura-2 Ca<sup>2+</sup> imaging, we demonstrated that both Orai1 and STIM1 require S-acylation to form active CRAC channels and mediate SOCE. Lastly, our studies using total internal reflection fluorescence microscopy showed that a lack of S-acylation of either Orai1 or STIM1 resulted in significantly reduced Orai1/STIM1 colocalization as evident from the diminished PM puncta formation. These data describe a novel form of SOCE regulation in T cells that may provide new therapeutic avenues to treat diseases caused by dysfunctional CRAC channels, such as severe combined immunodeficiency and Störmorken syndrome.</p>","abstract_has_math":false,"creators":["Diaz, Savannah J. West","0000-0002-2106-7680
"],"institution":null,"degree_name":"Doctor of Philosophy (PhD)","degree_level":"Dissertation (PhD)","degree_discipline":null,"degree_department":null,"school":null,"contributors":["Askar Akimzhanov, PhD","Darren Boehning, PhD","Ilya Levental, PhD"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2023,"date_issued":"2023-01-01T08:00:00Z","date_published":"2023-01-01T08:00:00Z","updated_at":"2026-07-24T05:50:24Z","subjects":["S-acylation","calcium signaling","T cells","palmitoylation","DHHC enzymes","Biochemistry, Biophysics, and Structural Biology","Cell Biology"],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://digitalcommons.library.tmc.edu/utgsbs_dissertations/1242","outbound_label":"Repository record","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Askar Akimzhanov, PhD","Darren Boehning, PhD","Ilya Levental, PhD"]},{"key":"dc:creator","label":"Author","values":["Diaz, Savannah J. West","0000-0002-2106-7680
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"]},{"key":"dc:title","label":"Title","values":["S-Acylation Is A Key Regulator of Orai1/Stim1-Mediated Store-Operated Calcium Entry In T Cells"]}]}],"canonical_facts":{"dc:contributor":["Askar Akimzhanov, PhD","Darren Boehning, PhD","Ilya Levental, PhD"],"dc:creator":["Diaz, Savannah J. West","0000-0002-2106-7680
"],"dc:date.available":["2024-01-30T08:00:00Z"],"dc:description.abstract":["Orai1 and STIM1 proteins are the essential components of the Ca2+ release activated Ca2+ (CRAC) channel which is required for store-operated Ca2+ entry (SOCE) in T cells and subsequent signaling events leading to T cell activation, proliferation, and differentiation. Plasma membrane (PM)-localized Orai1 is the pore-forming subunit of the CRAC channel, and STIM1 is the Ca2+ sensor localized to the endoplasmic reticulum (ER) membrane in quiescent T cells. T cell receptor (TCR) stimulation leads to depletion of ER Ca2+ stores resulting in Ca2+ no longer being bound to STIM1. This activates STIM1 by triggering a lengthening conformational change which allows it to bind Orai1 at ER-PM junctions within the immunological synapse. Binding of STIM1 to Orai1 activates the CRAC channel resulting in SOCE. Although the functional importance of these events is well-known, the molecular mechanism supporting timely and efficient recruitment of both Orai1 and STIM1 to the ER-PM junctions remains poorly understood. We have found that, among several other TCR machinery proteins, both Orai1 and STIM1 are rapidly and transiently S-acylated upon TCR stimulation. Furthermore, using electrophysiology studies and Fura-2 Ca2+ imaging, we demonstrated that both Orai1 and STIM1 require S-acylation to form active CRAC channels and mediate SOCE. Lastly, our studies using total internal reflection fluorescence microscopy showed that a lack of S-acylation of either Orai1 or STIM1 resulted in significantly reduced Orai1/STIM1 colocalization as evident from the diminished PM puncta formation. These data describe a novel form of SOCE regulation in T cells that may provide new therapeutic avenues to treat diseases caused by dysfunctional CRAC channels, such as severe combined immunodeficiency and Störmorken syndrome.
"],"dc:identifier":["https://digitalcommons.library.tmc.edu/utgsbs_dissertations/1242"],"dc:subject":["S-acylation","calcium signaling","T cells","palmitoylation","DHHC enzymes","Biochemistry, Biophysics, and Structural Biology","Cell Biology"],"dc:title":["S-Acylation Is A Key Regulator of Orai1/Stim1-Mediated Store-Operated Calcium Entry In T Cells"],"thesis:degree_level":["Dissertation (PhD)"],"thesis:degree_name":["Doctor of Philosophy (PhD)"]},"updated_at":"2026-07-24T05:50:24Z"}