Table 1.

Plant caspase-like activities and ER stress-induced PCD.

Protease	Preferred caspase substrate	Reference	Species	Comments
Vacuolar processing enzyme (VPE)	YVAD, caspase-1-like	Hatsugai etal. (2004), Qiang etal. (2012), Mendes etal. (2013)	Arabidopsis, soybean, N. benthamiana	Controls tonoplast rupture during PCD. Positively regulate ER stress-induced PCD.
Proteasome subunit β 1 (PBA1)	DEVD, caspase-3-like	Hatsugai etal. (2009), Han etal. (2012)	Arabidopsis, poplar	Mediates PCD during HR. Activity detected during ER stress-induced PCD
Phytaspase	VEID, caspase-6-like	Chichkova etal. (2010)	N. tabacum, rice	Mediates HR and ROS-induced PCD. Not reported in ER stress-induced PCD.
Saspase	VEHD, caspase-6-like; IETD, caspase-8-like	Coffeen and Wolpert (2004)	Oat	Not reported in ER stress-induced PCD