Dynamic and Irregular Distribution of RyR2 Clusters in the Periphery of Live Ventricular Myocytes
Por:
Hiess, F, Detampel, P, Nolla-Colomer, C, Vallmitjana, A, Ganguly, A, Amrein, M, ter Keurs, HEDJ, Benitez, R, Hove-Madsen, L, Chen, SRW
Publicada:
23 ene 2018
Resumen:
Cardiac ryanodine receptors (RyR2s) are Ca2+ release channels clustering in the sarcoplasmic reticulum membrane. These clusters are believed to be the elementary units of Ca2+ release. The distribution of these Ca2+ release units plays a critical role in determining the spatio-temporal profile and stability of sarcoplasmic reticulum Ca2+ release. RyR2 clusters located in the interior of cardiomyocytes are arranged in highly ordered arrays. However, little is known about the distribution and function of RyR2 clusters in the periphery of cardiomyocytes. Here, we used a knock-in mouse model expressing a green fluorescence protein (GFP)-tagged RyR2 to localize RyR2 clusters in live ventricular myocytes by virtue of their GFP fluorescence. Confocal imaging and total internal reflection fluorescence microscopy was employed to determine and compare the distribution of GFP-RyR2 in the interior and periphery of isolated live ventricular myocytes and in intact hearts. We found tightly ordered arrays of GFP-RyR2 clusters in the interior, as previously described. In contrast, irregular distribution of GFP-RyR2 clusters was observed in the periphery. Time-lapse total internal reflection fluorescence imaging revealed dynamic movements of GFP-RyR2 clusters in the periphery, which were affected by external Ca2+ and RyR2 activator (caffeine) and inhibitor (tetracaine), but little detectable movement of GFP-RyR2 clusters in the interior. Furthermore, simultaneous Ca2+- and GFP-imaging demonstrated that peripheral RyR2 clusters with an irregular distribution pattern are functional with a Ca2+ release profile similar to that in the interior. These results indicate that the distribution of RyR2 clusters in the periphery of live ventricular myocytes is irregular and dynamic, which is different from that of RyR2 clusters in the interior.
Filiaciones:
Hiess, F:
Univ Calgary, Libin Cardiovasc Inst Alberta, Dept Physiol & Pharmacol, Calgary, AB, Canada
Detampel, P:
Univ Basel, Dept Pharmaceut Sci, Basel, Switzerland
Nolla-Colomer, C:
Univ Politecn Catalunya Barcelona Tech, Dept Automat Control, Barcelona, Spain
Vallmitjana, A:
Univ Politecn Catalunya Barcelona Tech, Dept Automat Control, Barcelona, Spain
Ganguly, A:
Univ Calgary, Dept Microbiol Immunol & Infect Dis, Calgary, AB, Canada
Amrein, M:
Univ Calgary, Dept Biol & Anat, Calgary, AB, Canada
ter Keurs, HEDJ:
Univ Calgary, Libin Cardiovasc Inst Alberta, Dept Physiol & Pharmacol, Calgary, AB, Canada
Benitez, R:
Univ Politecn Catalunya Barcelona Tech, Dept Automat Control, Barcelona, Spain
Hove-Madsen, L:
Hosp Santa Creu & Sant Pau, Biomed Res Inst Barcelona CSIC IIBB, Barcelona, Spain
Chen, SRW:
Univ Calgary, Libin Cardiovasc Inst Alberta, Dept Physiol & Pharmacol, Calgary, AB, Canada
Green Published, Bronze
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