Galectin

Galectin-1 is a protein that in humans is encoded by the LGALS1 gene. LGALS1 contains four exons. The galectin-1 protein is 135 amino acids in length and highly conserved across species. It can be found in the nucleus, the cytoplasm, the cell surface and in the extracellular space. Galectins in general lack a traditional signal sequence, but are still secreted across the plasma membrane. This non-traditional secretion requires a functional glycan binding site. Galectin 1 contains a single carbohydrate recognition domain through which it can bind glycans both as a monomer and as a homodimer. Dimers are non-covalently bound and will spontaneously disassociate in low concentration. Galectin 1 does not bind glycans when oxidized. Having 6 cysteine residues, the oxidation state has a significant effect on the protein structure. The oxidized form is reported to have alternative functions not involving carbohydrate binding.