TTLL1
Domain
Gln-144 is the main determinant for regioselectivity, which segregates between initiases and elongases in all tubulin--tyrosine ligase family. A glutamine residue at this position is found in elongases TTLL6, TTLL9, TTLL11, TTLL13, TTLL10 and favors glutamate-chain elongation, whereas an arginine residue is found in initiases TTLL2, TTLL4, TTLL5, TTLL3, TTLL8 and favors initiation.
Function
Catalytic subunit of a polyglutamylase complex which modifies tubulin, generating side chains of glutamate on the gamma-carboxyl group of specific glutamate residues within the C-terminal tail of tubulin (PubMed:34782749). Probably involved in the side-chain elongation step of the polyglutamylation reaction rather than the initiation step. Modifies both alpha- and beta-tubulins with a preference for the alpha-tail. Unlike most polyglutamylases of the tubulin--tyrosine ligase family, only displays a catalytic activity when in complex with other proteins as it is most likely lacking domains important for autonomous activity. Part of the neuronal tubulin polyglutamylase complex. Mediates cilia and flagella polyglutamylation which is essential for their biogenesis and motility. Involved in respiratory motile cilia function through the regulation of beating asymmetry. Essential for sperm flagella biogenesis, motility and male fertility. Involved in KLF4 glutamylation which impedes its ubiquitination, thereby leading to somatic cell reprogramming, pluripotency maintenance and embryogenesis.
Sequence Similarities
Belongs to the tubulin polyglutamylase family.
Tissue Specificity
Expressed in a wide range of tissues. Has a stronger expression in heart, brain and testis.
Cellular localization
- Cytoplasm
- Cytoskeleton
- Cytoplasm
- Cytoskeleton
- Cilium basal body
- Cytoplasm
- Cytoskeleton
- Cilium axoneme
- Cell projection
- Cilium
- Flagellum
Alternative names
C22orf7, TTLL1, Polyglutamylase complex subunit TTLL1, Tubulin polyglutamylase TTLL1, Tubulin polyglutamylase complex subunit 3, Tubulin--tyrosine ligase-like protein 1, PGs3