. 2019 Jun 14;33(8):9030–9043. doi: 10.1096/fj.201800263RR

TABLE 2.

Keratin acetylation/methylation and protein stability

Variant	Mutations in acetylation sites	Mutations in methylation sites	Liver disease-associated keratin mutants
Variant	Mutations in acetylation sites	Mutations in methylation sites	K8 mutants	K18 mutants
K8/K18 constructs	K8 K108R, K8 K207R, K18 K187/426R	K8 R47K/A,	Y54H, G62C, R341H, G434S, I466fs	del65-72, I150V
K8/K18 constructs	K8 K108R, K8 K207R, K18 K187/426R	K18 R55K/A	Y54H, G62C, R341H, G434S, I466fs	del65-72, I150V
Acetylation	↓	ND	K8 G434S^b ↓	K18 del65-72 ↔
Acetylation	↓	ND	Other mutants^b ↑	K18 I150V^b ↑
Methylation	ND	↓	K8 mutants ↔	K18 del65-72^b ↑
Methylation	ND	↓	K8 mutants ↔	K18 I150V^b ↑
Keratin stability	K8 K108R ↔	K8 R47K/A^b ↓	ND^a	K18 del65-72^b ↑
	K8 K207R ↔	K18 R55K/A^b ↓		K18 I150V^b ↑
	K18 K187/426R ↔

Note that K18 I150V mutation increased both acetylation and methylation, whereas K18 del65–72 mutation up-regulated mainly methylation. It is speculated that additional acetylation on highly methylated keratins has a synergistic effect on prolonged protein stability. ND, not determined. ^aBecause liver disease–associated K8 mutants showed the similar level of methylation as compared with that of K8 WT (Fig. 5C), the keratin stability was not examined. ^bThe significant change of indicated level. Symbols indicated ↓ decrease, ↑ increase, and ↔ no significant change as compared with WT.