Tubb3

Domain

The highly acidic C-terminal region may bind cations such as calcium.

Function

Tubulin is the major constituent of microtubules. It binds two moles of GTP, one at an exchangeable site on the beta chain and one at a non-exchangeable site on the alpha chain. TUBB3 plays a critical role in proper axon guidance and maintenance (By similarity). Binding of NTN1/Netrin-1 to its receptor UNC5C might cause dissociation of UNC5C from polymerized TUBB3 in microtubules and thereby lead to increased microtubule dynamics and axon repulsion (By similarity). Plays a role in dorsal root ganglion axon projection towards the spinal cord (By similarity).

Post-translational modifications

Some glutamate residues at the C-terminus are polyglycylated, resulting in polyglycine chains on the gamma-carboxyl group. Glycylation is mainly limited to tubulin incorporated into axonemes (cilia and flagella) whereas glutamylation is prevalent in neuronal cells, centrioles, axonemes, and the mitotic spindle. Both modifications can coexist on the same protein on adjacent residues, and lowering polyglycylation levels increases polyglutamylation, and reciprocally. The precise function of polyglycylation is still unclear.

Some glutamate residues at the C-terminus are polyglutamylated, resulting in polyglutamate chains on the gamma-carboxyl group (By similarity). Polyglutamylation plays a key role in microtubule severing by spastin (SPAST). SPAST preferentially recognizes and acts on microtubules decorated with short polyglutamate tails: severing activity by SPAST increases as the number of glutamates per tubulin rises from one to eight, but decreases beyond this glutamylation threshold (By similarity).

Phosphorylated on Ser-172 by CDK1 during the cell cycle, from metaphase to telophase, but not in interphase. This phosphorylation inhibits tubulin incorporation into microtubules.

Sequence similarities

Belongs to the tubulin family.

Cellular localization

• Cytoplasm
• Cytoskeleton
• Cell projection
• Growth cone
• Cell projection
• Lamellipodium
• Cell projection
• Filopodium

Alternative names

• Tubulin beta-3 chain
• Neuron-specific class III beta-tubulin
• Tubb3

Database links

• entrezGene:246118
• swissprot:Q4QRB4

Target type

Proteins

Primary research area

Neuroscience

Other research areas

• Immunology & Infectious Disease

Molecular weight

50419Da