Table 1.

Posttranslational Modifications of tubulin and microtubules.

Modification	α/β	site	enzyme	references
Acetylation Deacetylation	α α	Lys40	TAT (MEC17) HDAC6, SIRT2, HDAC5	[58] [83, 89, 92]
Detyrosination Tyrosination	α α	C-Terminal Tyr Add to C-terminal	Unknown TTL	[3] [10, 11, 17]
Δ2deglutamylation)	α	Removal of C-terminal Glu of detyrosinated MTs	CCP1, CCP2, CCP3, CCP4, CCP5, and CCP6	[35, 37]
Glutamylation Deglutamylation of branch point Glu	α/β α/β	Various C-terminal Glu	TTLL4, 5, and 7 CCP5 & CCP1, CCP4, CCP6	[3, 4] [36, 37]
Polyglutamylation Deglutamylation to shorten polyGlu side chain	α/β	Add γ-linked Glu to C-terminal	TTLL1, 6, 11 and 13 CCP1, CCP4, CCP6	[3, 4] [37]
Glycylation Polyglycylation Deglycylation	α/β	Add γ-linked Gly to C-terminal Glu Addition to γ-linked Gly C-terminal	TTLL3 and 8 TTLL10 Unknown	[54, 55] [54] [3, 4]
Polyamination	α/β	β tubulins Q15, others	Transglutaminase	[2]
Glycososylation	α/β	various	Unknown	[4]
Glycation	α/β	various	Nonenzymatic	[118]
Palmitoylation	α	Cys376	Unknown	[121]
Phosphorylation	α/β	β tubulin Ser172, others	Various	[4]
Sumoylation	α	multiple	Unknown	[136, 137]
Ubiquitylation	α	Multiple	Parkin	[131]

Blue, modifications on tubulin in MTs; red, modifications restricted to soluble tubulin dimers; and black, modifications that are either undetermined or occur on both.