CORNICHON sorting and regulation of GLR channels underlie pollen tube Ca 2+ homeostasis

Multiple, diverse, and complex Calcium currents characterize the developing pollen tube in the small mustard plant Arabidopsis and correlate with growth at the tip of the pollen tube. This system constitutes a practical model for screening for Ca 2+ -signaling mechanisms in plants. Wudick et al. analyzed multiple variants of glutamate receptor–like (GLR) channels and discovered that some work alone and others work in pairs or trios. Subcellular localization of GLRs is a complex response to CORNICHON sorting proteins, which leave some GLRs at the plasma membrane and ferry others to internal calcium reservoirs. The calcium current at the tip of the growing pollen tube apparently integrates multiple intracellular currents. Science , this issue p. 533