Two proteins, STIM1 and Orai1, are vital for store-operated calcium entry, a process that enables cells to absorb calcium. When calcium levels in the ER dip, STIM1 oligomerizes and travels to the junction between the ER and the plasma membrane. There, it stimulates Orai1 to form a pore in the plasma membrane that admits calcium. Breast cancer cells require STIM1 and Orai1 to metastasize, but the underlying mechanism wasn’t clear.