TY  - JOUR
U1  - Wissenschaftlicher Artikel
A1  - Peckys, Diana B.
A1  - Gaa, Daniel
A1  - Alansary, Dalia
A1  - Niemeyer, Barbara A.
A1  - de Jonge, Niels
T1  - Supra-Molecular Assemblies of ORAI1 at Rest Precede Local Accumulation into Puncta after Activation
JF  - International journal of molecular sciences
N2  - The Ca2+ selective channel ORAI1 and endoplasmic reticulum (ER)-resident STIM proteins form the core of the channel complex mediating store operated Ca2+ entry (SOCE). Using liquid phase electron microscopy (LPEM), the distribution of ORAI1 proteins was examined at rest and after SOCE-activation at nanoscale resolution. The analysis of over seven hundred thousand ORAI1 positions revealed a number of ORAI1 channels had formed STIM-independent distinct supra-molecular clusters. Upon SOCE activation and in the presence of STIM proteins, a fraction of ORAI1 assembled in micron-sized two-dimensional structures, such as the known puncta at the ER plasma membrane contact zones, but also in divergent structures such as strands, and ring-like shapes. Our results thus question the hypothesis that stochastically migrating single ORAI1 channels are trapped at regions containing activated STIM, and we propose instead that supra-molecular ORAI1 clusters fulfill an amplifying function for creating dense ORAI1 accumulations upon SOCE-activation.
KW  - calcium channel
KW  - protein clusters
KW  - membrane protein
KW  - liquid phase electron microscopy
KW  - single molecule
Y1  - 2021
UN  - https://nbn-resolving.org/urn:nbn:de:bsz:291:415-814
U6  - https://doi.org/10.3390/ijms22020799
DO  - https://doi.org/10.3390/ijms22020799
VL  - 22
IS  - 2
SP  - 799
ER  -