Many dPCD-associated proteases accumulate as inactive proenzymes or in specific subcellular compartments before they are activated. Especially the vacuole, but also the ER and ER-derived vesicles can serve as storage space for inactive proteases. Once PCD execution is triggered, the breakup of cellular compartments is thought to release these proteases into the same compartments as their targets. The specific chemical environment of subcellular compartments before and after compartment breakup can be an additional cue to activate PCD-associated proteases. Abbreviations are: A, apoplast; C, cell wall; Ch, chloroplast; ER, endoplasmic reticulum; M, mitochondrion; N, nucleus; PM, plasma membrane; R, ricinosome; V, vacuole.