Exocyst complex is known to function in the exocytosis network, however, the molecular mechanism is unclear yet. Using UV/trimethylpsoralen mutagenesis, the sec-10 (one component of the exocyst complex) knockout mutant of C. elegans was obtained for the first time. The drug sensitive assays revealed clearly that the sec-10 gene affected the neural signal transmission, however, the electrophysiological assay showed the function of the ionotropic receptors in the neuromuscular junctions (NMJs) were unaltered compared with the wild type (WT). Thus it was assumed that the sec-10 gene might not influence the known ionotropic receptors in the NMJs, but some other pathways instead.

STIM1 is recognized as an ER Ca2+ sensor of calcium release-activated calcium (CRAC) channel that is constructed by membrane protein Orai1, However, this regulatory system may also be regulated by other proteins. Reticulocalbin 2 (RCN2) was purified and identified from STIM1-Orai1 complex. Confocal microscopy revealed that RCN2 co-localized with STIM1 in ER before and after Ca2+ store depletion. Single cell [Ca2+]I measurements of RCN2 EF hands mutant showed slight influence on SOC electrophysiological characters. Furthermore, a novel collar form aggregation of RCN2 surrounding STIM1 clusters suggested that RCN2 potentially plays a role of structure maintenance in STIM1 clustering.