微管蛋白β3重组兔单抗

TUBB3

Tubulin beta-3 chain

Dimer of alpha and beta chains.

Cytoplasm, cytoskeleton.

Expression is primarily restricted to centraland peripheral nervous system. Greatly increased expression in mostcancerous tissues.

Some glutamate residues at the C-terminus arepolyglutamylated. This modification occurs exclusively on glutamateresidues and results in polyglutamate chains on the gamma-carboxylgroup. Also monoglycylated but not polyglycylated due to theabsence of functional TTLL10 in human. Monoglycylation is mainlylimited to tubulin incorporated into axonemes (cilia and flagella)whereas glutamylation is prevalent in neuronal cells, centrioles,axonemes, and the mitotic spindle. Both modifications can coexiston the same protein on adjacent residues, and lowering glycylationlevels increases polyglutamylation, and reciprocally. The precisefunction of such modifications is still unclear but they regulatethe assembly and dynamics of axonemal microtubules (Probable).
Phosphorylated on Ser-172 by CDK1 during the cell cycle, frommetaphase to telophase, but not in interphase. This phosphorylationinhibits tubulin incorporation into microtubules.

Defects in TUBB3 are the cause of congenital fibrosis ofextraocular muscles type 3A (CFEOM3A) [MIM:600638]. A congenitalocular motility disorder marked by restrictive ophthalmoplegiaaffecting extraocular muscles innervated by the oculomotor and/ortrochlear nerves. It is clinically characterized by anchoring ofthe eyes in downward gaze, ptosis, and backward tilt of the head.Congenital fibrosis of extraocular muscles type 3 presents as anon-progressive, autosomal dominant disorder with variableexpression. Patients may be bilaterally or unilaterally affected,and their oculo-motility defects range from completeophthalmoplegia (with the eyes fixed in a hypo- and exotropicposition), to mild asymptomatic restrictions of ocular movement.Ptosis, refractive error, amblyopia, and compensatory headpositions are associated with the more severe forms of thedisorder. In some cases the ocular phenotype is accompanied byadditional features including developmental delay, corpus callosumagenesis, basal ganglia dysmorphism, facial weakness,polyneuropathy.
Defects in TUBB3 are the cause of cortical dysplasiacomplex with other brain malformations (CDCBM) [MIM:614039]. CDCBMis a disorder of aberrant neuronal migration and disturbed axonalguidance. Affected individuals have mild to severe mentalretardation, strabismus, axial hypotonia, and spasticity. Brainimaging shows variable malformations of cortical development,including polymicrogyria, gyral disorganization, and fusion of thebasal ganglia, as well as thin corpus callosum, hypoplasticbrainstem, and dysplastic cerebellar vermis. Extraocular musclesare not involved.

Belongs to the tubulin family.

Tubulin is the major constituent of microtubules. Itbinds two moles of GTP, one at an exchangeable site on the betachain and one at a non-exchangeable site on the alpha chain. TUBB3plays a critical role in proper axon guidance and mantainance.