Table 2 -.

Major variant-specific PTMs of histone H1, “?” indicates uncertainty of modification in the respective variant.

H1 PTM	Site conserved	Variant Specificity	Writer	Reader	Eraser	Function	Dependency	Citation
S2ph	H1.2, H1.3, H1.4, H1.5	H1.2, H1.3, H1.4, H1.5	Aurora B Kinase, PKA, GSK3			Cell cycle/Mitosis		Zheng,[42] Talasz[43] Alexandrow[44]
T18ph	H1.3, H1.4	H1.3, H1.4	Aurora B Kinase, PKA, GSK3			Mitosis		Andres[40]
T146ph	H1.2, H1.3, H1.4	H1.2, H1.4	Aurora B Kinase, PKA, GSK3					Chen[33]
S17ph	H1.5	H1.5				Activates Transcription		Izzo[45]
T154ph	H1.2, H1.3, H1.4, H1.5	H1.2, H1.4, H1.5	Aurora B Kinase, PKA, GSK3					Izzo Chen [33, 45]
S172/173ph	H1.2, H1.3, H1.4	S173 is high in H1.2, S172 is high in H1.4	Aurora B Kinase, PKA, GSK3			Activates Transcription		Chen Zheng[33, 42]
S187ph	H1.3, H1.4, H1.5	H1.3, H1.4, H1.5	Aurora B Kinase, PKA, GSK3					Izzo [45]
S35ph	H1.2, H1.3, H1.4	High in H1.4	PKA					Happel[29]
S2ac	H1.2, H1.3, H1.4, H1.5		GNC5	PHD/BRDs	HDAC	Activates Transcription		Andres[40]
K26ac	H1.2, H1.3, H1.4, H1.5	H1.4	SirT1			Activates Transcription		Vaquero[39]
K34ac	H1.2, H1.3, H1.4, H1.5	? in H1.5, high in H1.4	GCN5			Activates Transcription		Kamieniarz Izzo[38, 45]
K26me	H1.2, H1.3, H1.4, H1.5	High in H1.4	G9a/EZH2		KDM4	Represses Transcription	Blocked by S27ph	Trojer Walport Daujat [46–48]
K84ac	H1.1, H1.2, H1.3, H1.4, H1.5	H1.4	PCAF		HDAC1	DNA Damage		Chu[49]
K52me	H1.2, H1.3, H1.4, H1.5	? in H1.5				Represses Transcription		Allfrey[50]
K46ub	H1.2, H1.3, H1.4, H1.5	? in H1.5	RNF8			Double stranded break repair		Wong[41]
K63ub	H1.2, H1.3, H1.4, H1.5	H1.2	RNF8-UBC3			Double stranded break repair		Andres[40]