Table 1.

Summary of HIF-1α protein modifications.

Modifications	Enzymes or Oxidants Involved	Target Amino Acids	Outcomes	Reference
Prolyl hydroxylation	Prolyl hydroxylase domains (PHDs)	P402 and 564	Recognition signal for binding of pVHL E3 ligase	[109]
Polyubiquitination	pVHL E3 ligase	K	Signal for Degradation	[18] [110]
Acetylation	Arrest-defective-1 (ARD1)	K532	↑Interaction of HIF-1α with pVHL E3 ligase	[21]
Asparagine hydroxylation	Factor inhibiting HIF-1 (FIH-1)	N803	↓Interaction of HIF-1α with CBP/p300	[111]
Phosphorylation	MAPK	T796	↑Transcriptional activity	[23]
		S641 and 643	↑Transcriptional activity and nuclear localization	[26]
		S551, T555 and S589	Target for degradation	[26]
Oxidation	Hydroxyl radical	C800	HIF-1α degradation	[28]
	H2O2		HIF-1α degradation	[27]
Sumoylation	E3 SUMO ligase	Within ODD	↓Transcriptional activity	[34]
	E3 SUMO ligase	K391 and 477	↑Stability and transcriptional activity	[112]
	RWD-containing sumoylation enhancer (RSUME) and SUMO conjugase Ubc9		HIF-1α stabilization	[32]