P09642 · TBA3_CHICK
- ProteinTubulin alpha-3 chain
- StatusUniProtKB reviewed (Swiss-Prot)
- Organism
- Amino acids322 (go to sequence)
- Protein existenceInferred from homology
- Annotation score4/5
Function
function
Tubulin is the major constituent of microtubules, a cylinder consisting of laterally associated linear protofilaments composed of alpha- and beta-tubulin heterodimers. Microtubules grow by the addition of GTP-tubulin dimers to the microtubule end, where a stabilizing cap forms. Below the cap, tubulin dimers are in GDP-bound state, owing to GTPase activity of alpha-tubulin.
Miscellaneous
This tubulin does not have a C-terminal tyrosine.
There are at least seven alpha tubulin genes (alpha-1 to alpha-6, and alpha-8), and a pseudogene (alpha-7) in chicken.
Catalytic activity
- GTP + H2O = GDP + phosphate + H+This reaction proceeds in the forward direction.
Cofactor
Features
Showing features for binding site, active site.
Type | ID | Position(s) | Description | |||
---|---|---|---|---|---|---|
Binding site | 15 | GTP (UniProtKB | ChEBI) | ||||
Sequence: S | ||||||
Binding site | 19 | GTP (UniProtKB | ChEBI) | ||||
Sequence: G | ||||||
Binding site | 20 | GTP (UniProtKB | ChEBI) | ||||
Sequence: T | ||||||
Binding site | 54 | GTP (UniProtKB | ChEBI) | ||||
Sequence: T | ||||||
Binding site | 81 | GTP (UniProtKB | ChEBI) | ||||
Sequence: N | ||||||
Binding site | 103 | GTP (UniProtKB | ChEBI) | ||||
Sequence: N | ||||||
Active site | 129 | |||||
Sequence: E |
GO annotations
Aspect | Term | |
---|---|---|
Cellular Component | cytoplasm | |
Cellular Component | microtubule | |
Molecular Function | GTP binding | |
Molecular Function | hydrolase activity | |
Molecular Function | structural constituent of cytoskeleton | |
Biological Process | microtubule cytoskeleton organization | |
Biological Process | mitotic cell cycle |
Keywords
- Molecular function
- Ligand
Enzyme and pathway databases
Names & Taxonomy
Protein names
- Recommended nameTubulin alpha-3 chain
- EC number
Organism names
- Organism
- Taxonomic lineageEukaryota > Metazoa > Chordata > Craniata > Vertebrata > Euteleostomi > Archelosauria > Archosauria > Dinosauria > Saurischia > Theropoda > Coelurosauria > Aves > Neognathae > Galloanserae > Galliformes > Phasianidae > Phasianinae > Gallus
Accessions
- Primary accessionP09642
Proteomes
Organism-specific databases
Subcellular Location
PTM/Processing
Features
Showing features for chain.
Type | ID | Position(s) | Description | |||
---|---|---|---|---|---|---|
Chain | PRO_0000048149 | 1-322 | Tubulin alpha-3 chain | |||
Sequence: ADQCSGLQGFLVFHSFGGGTGSGFTSLLMERLSVEYSKKSKLEFSVYPDRQVSTAVVEPYNSILTTHTTLEHSDCSFMVDNEAIYDICNRNLDIERPTYTNLNRLIGQIVSSVTASLRFNGALNVDLIEFQTNLVPYPRIHFPLTTYARIISAEKAYHEQLSVPEITNACFEFSNQMVKCDPRRGKYMACCLLYRGDVVPKDVNAAIAAIKTRRSIQFVDWCPTGFKVGINYQPPTVVPGGDLAKVQRAVCMLSNTTAIAEAWARLDHKFDLMYAKRAFVHWYVGEGMEEGEFSEAREDLAALEKDYEEVGRNSADGGEFEE |
Post-translational modification
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).
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).
Interaction
Subunit
Dimer of alpha and beta chains. A typical microtubule is a hollow water-filled tube with an outer diameter of 25 nm and an inner diameter of 15 nM. Alpha-beta heterodimers associate head-to-tail to form protofilaments running lengthwise along the microtubule wall with the beta-tubulin subunit facing the microtubule plus end conferring a structural polarity. Microtubules usually have 13 protofilaments but different protofilament numbers can be found in some organisms and specialized cells.
Structure
Sequence
- Sequence statusFragment
- Length322
- Mass (Da)36,088
- Last updated1989-07-01 v1
- ChecksumBB39B41C9E916204
Features
Showing features for non-terminal residue.
Type | ID | Position(s) | Description | |||
---|---|---|---|---|---|---|
Non-terminal residue | 1 | |||||
Sequence: A |
Keywords
- Technical term