Fig. 5.

Schematic diagram illustrates the possible relationship between a mobile lysosome and the junctional complex formed between “docked” lysosome clusters and the S/ER. Also depicted is the generation of local, monoquantal Ca²⁺ release (A) and the development of a propagating Ca²⁺ wave by quantal recruitment of inositol 1,4,5-trisphosphate receptor (IP₃R) or ryanodine receptor (RyR) clusters on the S/ER (B). SERCA, S/ER Ca²⁺-ATPase.