tubulin-tyrosine ligase activity
Definition
Target type: molecularfunction
Catalysis of the reaction: ATP + detyrosinated alpha-tubulin + L-tyrosine = alpha-tubulin + ADP + phosphate. [EC:6.3.2.25]
Tubulin-tyrosine ligase activity refers to the enzymatic process of adding a tyrosine residue to the C-terminal end of alpha-tubulin. This modification, known as tyrosination, is crucial for the regulation of microtubule dynamics, stability, and function within the cell. The enzyme responsible for this process is tubulin tyrosine ligase (TTL), also known as tyrosyl-tRNA synthetase.
Tyrosination of tubulin plays a vital role in the dynamic instability of microtubules, a key characteristic that allows for their rapid assembly and disassembly during cellular processes. The addition of tyrosine to the alpha-tubulin subunit promotes the assembly of microtubules, while the removal of tyrosine by the enzyme carboxypeptidase E (CPE) promotes disassembly. This cycle of tyrosination and detyrosination contributes to the dynamic nature of microtubule networks and enables cells to efficiently respond to various stimuli.
Furthermore, tyrosination affects microtubule stability. Tyrosinated microtubules are generally more stable and resistant to depolymerization compared to detyrosinated microtubules. This stability is critical for maintaining microtubule structure and function in various cellular processes, including cell division, intracellular transport, and cell motility.
In addition, tyrosination influences microtubule interactions with motor proteins, such as dynein and kinesin. These proteins are responsible for transporting organelles and vesicles along microtubule tracks. Tyrosination modulates the affinity of these motor proteins for microtubules, thereby affecting the efficiency of intracellular transport.
Overall, tubulin-tyrosine ligase activity is essential for regulating microtubule dynamics, stability, and function through the precise addition of tyrosine to the C-terminal end of alpha-tubulin. This modification plays a crucial role in various cellular processes, highlighting the importance of TTL in maintaining cellular integrity and function.'
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Proteins (1)
| Protein | Definition | Taxonomy |
|---|---|---|
| Tubulin--tyrosine ligase | A tubulin--tyrosine ligase that is encoded in the genome of human. [PRO:DNx, UniProtKB:Q8NG68] | Homo sapiens (human) |
Compounds (3)
| Compound | Definition | Classes | Roles |
|---|---|---|---|
| tyrosine | tyrosine : An alpha-amino acid that is phenylalanine bearing a hydroxy substituent at position 4 on the phenyl ring. Tyrosine: A non-essential amino acid. In animals it is synthesized from PHENYLALANINE. It is also the precursor of EPINEPHRINE; THYROID HORMONES; and melanin. | amino acid zwitterion; erythrose 4-phosphate/phosphoenolpyruvate family amino acid; L-alpha-amino acid; proteinogenic amino acid; tyrosine | EC 1.3.1.43 (arogenate dehydrogenase) inhibitor; fundamental metabolite; micronutrient; nutraceutical |
| 3-nitrotyrosine | 3-nitrotyrosine : A nitrotyrosine comprising tyrosine having a nitro group at the 3-position on the phenyl ring. 3-nitrotyrosine: RN given refers to parent cpd without isomeric designation | 2-nitrophenols; C-nitro compound; nitrotyrosine; non-proteinogenic alpha-amino acid | |
| 3-aminotyrosine |