2026-04-29T15:25:25Zhttps://repisalud.isciii.es/rest/oai/request
oai:repisalud.isciii.es:20.500.12105/164492024-09-27T08:30:53Zcom_20.500.12105_19604com_20.500.12105_2051col_20.500.12105_19605
Repisalud author Tambeaux, Allison author Aguilar-Sánchez, Yuriana author Santiago, Demetrio J author Mascitti, Madeleine author DiNovo, Karyn M author Mejía-Alvarez, Rafael author Fill, Michael author Wayne Chen, S R author Ramos-Franco, Josefina funder National Institutes of Health (Estados Unidos) funder Heart and Stroke Foundation 2023-09-12T11:13:27Z 2023-09-12T11:13:27Z 2023-05 Pflugers Arch. 2023 May;475(5):569-581. 10.1007/s00424-023-02796-x 1432-2013 Pflugers Archiv : European journal of physiology 36881190 http://hdl.handle.net/20.500.12105/16449 Inositol 1,4,5-trisphosphate receptor (IP3R) and ryanodine receptor (RyR) are homologous cation channels that mediate release of Ca2+ from the endoplasmic/sarcoplasmic reticulum (ER/SR) and thereby are involved in many physiological processes. In previous studies, we determined that when the D2594 residue, located at or near the gate of the IP3R type 1, was replaced by lysine (D2594K), a gain of function was obtained. This mutant phenotype was characterized by increased IP3 sensitivity. We hypothesized the IP3R1-D2594 determines the ligand sensitivity of the channel by electrostatically affecting the stability of the closed and open states. To test this possibility, the relationship between the D2594 site and IP3R1 regulation by IP3, cytosolic, and luminal Ca2+ was determined at the cellular, subcellular, and single-channel levels using fluorescence Ca2+ imaging and single-channel reconstitution. We found that in cells, D2594K mutation enhances the IP3 ligand sensitivity. Single-channel IP3R1 studies revealed that the conductance of IP3R1-WT and -D2594K channels is similar. However, IP3R1-D2594K channels exhibit higher IP3 sensitivity, with substantially greater efficacy. In addition, like its wild type (WT) counterpart, IP3R1-D2594K showed a bell-shape cytosolic Ca2+-dependency, but D2594K had greater activity at each tested cytosolic free Ca2+ concentration. The IP3R1-D2594K also had altered luminal Ca2+ sensitivity. Unlike IP3R1-WT, D2594K channel activity did not decrease at low luminal Ca2+ levels. Taken together, our functional studies indicate that the substitution of a negatively charged residue by a positive one at the channels' pore cytosolic exit affects the channel's gating behavior thereby explaining the enhanced ligand-channel's sensitivity. eng Ligand sensitivity of type-1 inositol 1,4,5-trisphosphate receptor is enhanced by the D2594K mutation. journal article TElDRU5DSUEgREUgRElTVFJJQlVDScOTTiBOTyBFWENMVVNJVkEKCkFjZXB0YW5kbyBlc3RhIGxpY2VuY2lhLCBVc3RlZCAoZWwgYXV0b3IvZXMgbyBlbCBwcm9waWV0YXJpby9zIGRlIGxvcyBkZXJlY2hvcyBkZSAKYXV0b3IpIGNvbmNlZGUgYSBSRVBJU0FMVUQgZWwgZGVyZWNobyBubyBleGNsdXNpdm8gZGUgcmVwcm9kdWNpciwgY29udmVydGlyLCB5L28gCmRpc3RyaWJ1aXIgc3UgZG9jdW1lbnRvIChpbmNsdXllbmRvIHN1IHJlc3VtZW4pIGEgbml2ZWwgbXVuZGlhbCBlbiBmb3JtYXRvIGRpZ2l0YWwsIAppbmNsdXllbmRvLCBhdWRpbyB5IHbDrWRlbywgYSB0cmF2w6lzIGRlIHN1IHJlcG9zaXRvcmlvIGluc3RpdHVjaW9uYWwuCgpVc3RlZCBhY2VwdGEgcXVlIFJFUElTQUxVRCBwdWVkZSwgc2luIGFsdGVyYXIgc3UgY29udGVuaWRvLCBjb252ZXJ0aXIgc3UgZG9jdW1lbnRvIAphIGN1YWxxdWllciBvdHJvIGZvcm1hdG8gZGlnaXRhbCBkZSBkYXRvcywgYXVkaW8geSB2aWRlbywgY29uIGVsIHByb3DDs3NpdG8gZGUgcXVlIApwdWVkYSBzZXIgYWxvamFkbyBlbiBlbCByZXBvc2l0b3Jpby4gCgpVc3RlZCBlc3TDoSBkZSBhY3VlcmRvIGNvbiBxdWUgUkVQSVNBTFVEIHB1ZWRhIGNvbnNlcnZhciBtw6FzIGRlIHVuYSBjb3BpYSBkZSBlc3RlIApkb2N1bWVudG8gcGFyYSBhc2VndXJhciBzdSBzZWd1cmlkYWQsIHByZXNlcnZhY2nDs24geSBhY2Nlc28uCgpVc3RlZCBkZWNsYXJhIHF1ZSBlbCBkb2N1bWVudG8gZXMgdW4gdHJhYmFqbyBvcmlnaW5hbCwgeSBxdWUgdGllbmUgZWwgZGVyZWNobyBkZSAKb3RvcmdhciBsb3MgZGVyZWNob3MgY29udGVuaWRvcyBlbiBlc3RhIGxpY2VuY2lhLiBUYW1iacOpbiBkZWNsYXJhIHF1ZSBzdSBwZXRpY2nDs24gCm5vIGluZnJpbmdlIGxvcyBkZXJlY2hvcyBkZSBhdXRvciBkZSBuYWRpZS4gCgpTaSBlbCBkb2N1bWVudG8gY29udGllbmUgbWF0ZXJpYWxlcyBwYXJhIGxvcyBxdWUgbm8gc2UgdGllbmVuIGxvcyBkZXJlY2hvcyBkZSBhdXRvciwgClVzdGVkIGRlY2xhcmEgcXVlIGhhIG9idGVuaWRvIGVsIHBlcm1pc28gc2luIHJlc3RyaWNjacOzbiBkZWwgcHJvcGlldGFyaW8gZGUgbG9zIApkZXJlY2hvcyB5IHF1ZSBlbiBkaWNobyBtYXRlcmlhbCwgZXN0w6EgY2xhcmFtZW50ZSBpZGVudGlmaWNhZGEgeSByZWNvbm9jaWRhIHN1IAphdXRvcsOtYSBkZW50cm8gZWwgdGV4dG8gbyBkZWwgY29udGVuaWRvIGRlIGRpY2hvIGRvY3VtZW50by4gCgpTaSBlbCBlbnbDrW8gc2UgYmFzYSBlbiB1biB0cmFiYWpvIHF1ZSBoYSBzaWRvIHBhdHJvY2luYWRvIG8gYXBveWFkbyBwb3IgdW5hIGFnZW5jaWEgCnUgb3JnYW5pemFjacOzbiBkaXN0aW50YSBhIFJFUElTQUxVRCwgdXN0ZWQgYWNlcHRhIHF1ZSBoYSBjdW1wbGlkbyBjb24gZWwgZGVyZWNobyBkZSAKcmV2aXNpw7NuIHkgb3RyYXMgb2JsaWdhY2lvbmVzIHJlcXVlcmlkYXMgcG9yIGNvbnRyYXRvIG8gYWN1ZXJkby4gCgpSRVBJU0FMVUQgaWRlbnRpZmljYXLDoSBjbGFyYW1lbnRlIHN1KHMpIG5vbWJyZShzKSBjb21vIGF1dG9yKHMpIG8gcHJvcGlldGFyaW8ocykgCmRlbCBkb2N1bWVudG8sIHkgbm8gaGFyw6EgbmluZ3VuYSBhbHRlcmFjacOzbiwgZXhjZXB0byBzZWfDum4gbG8gcGVybWl0aWRvIHBvciBlc3RhIApsaWNlbmNpYS4gCg== URL https://repisalud.isciii.es/bitstreams/aeaccf7d-c42b-401e-bf32-9feb1af5b382/download File MD5 3cc7d4e67433939cf84423d960146fb1 4136960 application/pdf Ligand sensitivity_Pflugers Arch_2023.pdf URL https://repisalud.isciii.es/bitstreams/1cc81f56-06af-4c06-97b2-f12075fd84db/download File MD5 238f90fa1205f7a942919071a463f539 61574 text/plain Ligand sensitivity_Pflugers Arch_2023.pdf.txt