GABARAPL1 (GEC1): original or copycat?

The GABARAPL1 (GABARAP-LIKE 1) gene was first described as an early estrogen-regulated gene that shares a high sequence homology with GABARAP and is thus a part of the GABARAP family. GABARAPL1, like GABARAP, interacts with the GABAA receptor and tubulin and promotes tubulin polymerization. The GABARAP family members (GABARAP, GABARAPL1 and GABARAPL2) and their close homologs (LC3 and Atg8) are not only involved in the transport of proteins or vesicles but are also implicated in various mechanisms such as autophagy, cell death, cell proliferation and tumor progression. However, despite these similarities, GABARAPL1 displays a complex regulation that is different from that of other GABARAP family members. Moreover, it presents a regulated tissue expression and is the most highly expressed gene among the family in the central nervous system. In this review article, we will outline the specific functions of this protein and also hypothesize about the roles that GABARAPL1 might have in several important biological processes such as cancer or neurodegenerative diseases.