Table 1. Endogenous regulators of caspase-9.

Efficacy	Factor	Target	Mechanism of action	Reference(s)
Inhibition	ERK2	Caspase-9 (Thr125-P)	Inhibiting caspase-9 processing	[33, 58]
	DYRK1A	Caspase-9 (Thr125-P)	Inhibiting caspase-9 processing	[59–61]
	CDK1/cyclin B1	Caspase-9 (Thr125-P)	Inhibiting caspase-9 processing	[62]
	P38α MAPK	Caspase-9 (Thr125-P; most likely indirect)	Inhibiting caspase-9 processing	[60]
	Akt/PKB	Caspase-9 (Ser196-P)	Inhibiting caspase-9 processing	[32]
	PKCξ	Caspase-9 (Ser144-P)	Inhibiting caspase-9 processing	[36]
	PKA	Caspase-9(Ser99-P, Ser183-P, Ser195-P, but not required)	Inhibiting caspase-9 recruitment to the apoptosome? Unclear.	[37]
	CK2	Caspase-9 (Ser302-P, Ser307-P and Ser310-P) unclear	Inhibiting caspase-9 processing in murine cells. Unclear in human cells.	[38]
	XIAP	Caspase-9	Inhibiting processed caspase-9	[42, 43, 63, 64]
	TUCAN	Caspase-9	Inhibiting Apaf-1–caspase-9 interaction	[44]
	HBXIP	Caspase-9	Inhibiting Apaf-1–caspase-9 interaction as HBXIP–survivin complex	[45]
	HAX-1	Caspase-9	Inhibiting caspase-9 activity	[46, 47]
	NO	Caspase-9	Inhibiting caspase-9 activity by nitrosylation	[48, 49, 65]
Enhancement	c-Abl	Caspase-9	Enhancing caspase-9 processing	[41, 52]
	Nucling	Caspase-9	Enhancing apoptosome stability; transports to nucleus	[66]
	NAC/DEFCAP	Apaf-1 and Caspase-9	Enhancing caspase-9 recruitment to the apoptosome; mechanism unclear.	[53, 54]