The foot structure from the type 1 ryanodine receptor is required for functional coupling to store-operated channels.
In the present study we have explored structural determinants of the functional interaction between skeletal muscle ryanodine receptor (RyR1) and transient receptor potential channel 1 (TRPC1) channels expressed in Chinese hamster ovary cells. We have illustrated a functional interaction between TRPC1 channels and RyR1 for the regulation of store-operated calcium entry (SOCE) initiated after releasing calcium from a caffeine-sensitive intracellular calcium pool. RNA interference experiments directed to reduce the amount of TRPC1 protein indicate that RyR1 associates to at least two different types of store-operated channels (SOCs), one dependent and one independent of TRPC1. In contrast, bradykinin-induced SOCE is completely dependent on the presence of TRPC1 protein, as we have previously illustrated. Removing the foot structure from RyR1 results in normal caffeine-induced release of calcium from internal stores but abolishes the activation of SOCE, indicating that this structure is require for functional coupling to SOCs. The footless RyR1 protein shows a different cellular localization when compared with wild type RyR1. The later protein shows a higher percentage of colocalization with FM-464, a marker of plasma membrane. The implications of the foot structure for the functional and physical coupling to TRPC and SOCs is discussed.
Sampieri
Alicia
A
Departamento de Biología Celular, Instituto de Fisiología Celular and Departamento de Neurobiología Celular y Molecular, Instituto de Neurobiología, Universidad Nacional Autónoma de México, Ciudad Universitaria 04510, México.
Diaz-Muñoz
Mauricio
M
Antaramian
Anaid
A
Vaca
Luis
L
D000818:Animals; D015153:Blotting, Western; D001920:Bradykinin / Q000737:chemistry / Q000494:pharmacology; D016466:CHO Cells; D002110:Caffeine / Q000494:pharmacology; D002118:Calcium / Q000737:chemistry / Q000378:metabolism; D015220:Calcium Channels / Q000737:chemistry* / Q000378:metabolism; D002138:Calibration; D002462:Cell Membrane / Q000378:metabolism; D006224:Cricetinae; D003600:Cytosol / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004594:Electrophysiology; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence; D008954:Models, Biological; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D034622:RNA Interference; D012330:RNA, Double-Stranded; D012333:RNA, Messenger / Q000378:metabolism; D011817:Rabbits; D020133:Reverse Transcriptase Polymerase Chain Reaction; D019837:Ryanodine Receptor Calcium Release Channel / Q000737:chemistry*; D013347:Subcellular Fractions; D013997:Time Factors
D015220:Calcium Channels; D012330:RNA, Double-Stranded; D012333:RNA, Messenger; D019837:Ryanodine Receptor Calcium Release Channel; D002110:Caffeine; D001920:Bradykinin; D002118:Calcium