LOXL3
Function
Protein-lysine 6-oxidase that mediates the oxidation of peptidyl lysine residues to allysine in target proteins (PubMed:17018530, PubMed:28065600). Catalyzes the post-translational oxidative deamination of peptidyl lysine residues in precursors of elastin and different types of collagens, a prerequisite in the formation of cross-links between collagens and elastin (PubMed:17018530). Required for somite boundary formation by catalyzing oxidation of fibronectin (FN1), enhancing integrin signaling in myofibers and their adhesion to the myotendinous junction (MTJ) (By similarity). Acts as a regulator of inflammatory response by inhibiting differentiation of naive CD4(+) T-cells into T-helper Th17 or regulatory T-cells (Treg): acts by interacting with STAT3 in the nucleus and catalyzing both deacetylation and oxidation of lysine residues on STAT3, leading to disrupt STAT3 dimerization and inhibit STAT3 transcription activity (PubMed:28065600). Oxidation of lysine residues to allysine on STAT3 preferentially takes place on lysine residues that are acetylated (PubMed:28065600). Also able to catalyze deacetylation of lysine residues on STAT3 (PubMed:28065600).
Isoform 1
Shows protein-lysine 6-oxidase activity toward elastin and different types of collagens, with the highest activity toward collagen type VIII (PubMed:17018530).
Isoform 2
Shows protein-lysine 6-oxidase activity toward elastin and different types of collagens, with the highest activity toward collagen type IV (PubMed:17018530).
Involvement in disease
Defects in LOXL3 are found in a family with an autosomal recessive form of Stickler syndrome, an inherited disorder that associates ocular signs with more or less complete forms of Pierre Robin sequence and sensorineural deafness (PubMed:25663169). Pierre Robin sequence includes an opening in the roof of the mouth (a cleft palate) (PubMed:25663169). The degree of hearing loss varies among affected individuals and may become more severe over time (PubMed:25663169). Syndrome expressivity is variable (PubMed:25663169). Ocular disorders include non-progressive myopia with associated chorioretinal degeneration (PubMed:25663169).
Myopia 28, autosomal recessive
MYP28
A form of myopia, a refractive error of the eye, in which parallel rays from a distant object come to focus in front of the retina, vision being better for near objects than for far. MYP28 patients are affected by early-onset high myopia in the first decade of life. Retinal detachment may occur, and early-onset cataract has been reported.
None
The disease is caused by variants affecting the gene represented in this entry.
Post-translational modifications
The lysine tyrosylquinone cross-link (LTQ) is generated by condensation of the epsilon-amino group of a lysine with a topaquinone produced by oxidation of tyrosine.
Sequence Similarities
Belongs to the lysyl oxidase family.
Tissue Specificity
Isoform 1: Predominantly detected in the heart, placenta, lung, and small intestine (PubMed:17018530). Isoform 2: Highly detected in the kidney, pancreas, spleen, and thymus, and is absent in lung (PubMed:17018530). In eye, present in all layers of corneas as well as in the limbus and conjunctiva (at protein level) (PubMed:26218558).
Cellular localization
- Secreted
- Extracellular space
- Cytoplasm
- Nucleus
- It is unclear how LOXL3 is both intracellular (cytoplasmic and nuclear) and extracellular: it contains a clear signal sequence and is predicted to localize in the extracellular medium. However, the intracellular location is clearly reported and at least another protein of the family (LOXL2) also has intracellular and extracellular localization despite the presence of a signal sequence (PubMed:28065600).
- Isoform 1
- Secreted
- Extracellular space
- Isoform 2
- Cytoplasm
- Secreted
- Extracellular space
Alternative names
LOXL, LOXL3, Lysyl oxidase homolog 3, Lysyl oxidase-like protein 3