Galectin-8: a complex sub-family of galectins (Review).

Galectins are animal lectins, that can specifically bind beta-galactosides. Twelve galectins have been described in vertebrates, belonging to three different groups: prototype, tandem-repeat and chimeric. These proteins seem to be involved in cellular interactions and neoplastic transformations. We present an overview of a particular galectin member: galectin-8. This galectin, which has been intensively studied over the last six years, presents a particular type of gene regulation. It is widely expressed in tumoral tissues and seems to be involved in integrin-like cell interactions. Studies show that the LGALS8 gene encodes for almost seven mRNAs by alternative splicing pathways and various polyadenylation sites. These mRNAs could encode for six isoforms of galectin-8, of which three belong to the tandem-repeat galectin group (with two carbohydrate binding domains) and the three others to the prototype group (one carbohydrate binding domain). All these isoforms seem to be differentially expressed in various tumoral cells. This untypical galectin-8 subfamily seems to have a complex expression regulation, that could be involved in cancer phenomena.