Skip to content

Research at St Andrews

Ca2+-dependent phosphorylation of RyR2 can uncouple channel gating from direct cytosolic Ca2+ regulation

Research output: Contribution to journalArticle

Author(s)

Simon Carter, Samantha Jane Pitt, John Colyer, Rebecca Sitsapesan

School/Research organisations

Abstract

Phosphorylation of the cardiac ryanodine receptor (RyR2) is thought to be important not only for normal cardiac excitation-contraction coupling but also in exacerbating abnormalities in Ca2+ homeostasis in heart failure. Linking phosphorylation to specific changes in the single-channel function of RyR2 has proved very difficult, yielding much controversy within the field. We therefore investigated the mechanistic changes that take place at the single-channel level after phosphorylating RyR2 and, in particular, the idea that PKA-dependent phosphorylation increases RyR2 sensitivity to cytosolic Ca2+. We show that hyperphosphorylation by exogenous PKA increases open probability (P(o)) but, crucially, RyR2 becomes uncoupled from the influence of cytosolic Ca2+; lowering [Ca²+] to subactivating levels no longer closes the channels. Phosphatase (PP1) treatment reverses these gating changes, returning the channels to a Ca2+-sensitive mode of gating. We additionally found that cytosolic incubation with Mg2+/ATP in the absence of exogenously added kinase could phosphorylate RyR2 in approximately 50% of channels, thereby indicating that an endogenous kinase incorporates into the bilayer together with RyR2. Channels activated by the endogenous kinase exhibited identical changes in gating behavior to those activated by exogenous PKA, including uncoupling from the influence of cytosolic Ca2+. We show that the endogenous kinase is both Ca2+-dependent and sensitive to inhibitors of PKC. Moreover, the Ca2+-dependent, endogenous kinase-induced changes in RyR2 gating do not appear to be related to phosphorylation of serine-2809. Further work is required to investigate the identity and physiological role of this Ca2+-dependent endogenous kinase that can uncouple RyR2 gating from direct cytosolic Ca2+ regulation.

Close

    Research areas

  • Calcium-release channel, Ion-channel, Ryanodine receptor, excitation-contraction coupling

Discover related content
Find related publications, people, projects and more using interactive charts.

View graph of relations

Related by author

  1. Allosteric activation of an ion channel triggered by modification of mechanosensitive nano-pockets

    Kapsalis, C., Wang, B., El Mkami, H., Pitt, S. J., Schnell, J., Smith, T. K., Lippiat, J., Bode, B. E. & Pliotas, C., 10 Oct 2019, In : Nature Communications. 10, 14 p., 4619.

    Research output: Contribution to journalArticle

  2. Plasma non-esterified fatty acids contribute to increased coagulability in type-2 diabetes through altered plasma zinc speciation

    Sobczak, A. I. S., Katundu, K. G. H., Phoenix, F. A., Khazaipoul, S., Yu, R., Lampiao, F., Stefanowicz, F., Blindauer, C. A., Pitt, S. J., Smith, T. K., Ajjan, R. A. & Stewart, A. J., 28 Aug 2019, In : biorxiv. 38 p.

    Research output: Contribution to journalArticle

  3. Total plasma magnesium, zinc, copper and selenium concentrations in type-I and type-II diabetes

    Sobczak, A. I. S., Stefanowicz, F., Pitt, S. J., Ajjan, R. A. & Stewart, A. J., Feb 2019, In : BioMetals. 32, 1, p. 123-138 16 p.

    Research output: Contribution to journalArticle

  4. FUNCTIONAL CHARACTERIZATION OF ATP2C2, A RISK FACTOR FOR LANGUAGE DISORDERS

    Martinelli, A., Diaz, R., Feliciotti, I., Pitt, S. & Paracchini, S., 2019, In : European Neuropsychopharmacology. 29, p. 1194-1195 2 p.

    Research output: Contribution to journalAbstract

  5. Influence of zinc on glycosaminoglycan neutralisation during coagulation

    Sobczak, A. I. S., Pitt, S. J. & Stewart, A. J., Sep 2018, In : Metallomics. 10, 9, p. 1180-1190 11 p.

    Research output: Contribution to journalReview article

Related by journal

  1. An investigation into membrane bound redox carriers involved in energy transduction mechanism in Brevibacterium linens DSM 20158 with unsequenced genome

    Shabbiri, K., Botting, C. H., Adnan, A., Fuszard, M., Naseem, S., Ahmed, S., Shujaat, S., Syed, Q. & Ahmad, W., Apr 2014, In : Journal of Membrane Biology. 247, 4, p. 345-355 11 p.

    Research output: Contribution to journalArticle

ID: 48702027

Top