P2RY1 and astrocytoma (excluding glioblastoma): Our previous research (Ferreira et al., 2012) using an ELISA-based assay showed that expression of a nonphosphorylatable mutant CLCb where all 19 serines had been mutated to alanines, CLCbSallA, inhibited internalization of both the GPCR purinergic receptors P2Y1 and P2Y12 in 1321N1 astrocytoma cell lines, which stably expressed HA-tagged receptors.