Lengsin, lens protein with glutamine synthetase domain (LGSN)

Lengsin (LGSN) is a human protein encoded by the LGSN gene, structurally related to the glutamine synthetase (GS) superfamily, specifically the GS I branch, but it lacks enzymatic glutamine synthesis activity and is considered a pseudo-glutamine synthetase[1][2][3][5]. Lengsin is abundantly and specifically expressed in the lens, particularly in terminally differentiating secondary fiber cells, where it likely acts as a chaperone or structural component, facilitating intermediate filament reorganization and contributing to lens transparency and homeostasis[1][2][3][4][5]. Alternative splicing produces variants, one of which (splicing variant 4) is abnormally expressed in lung cancer, where it may promote cell survival and serve as a cancer antigen and potential immunotherapy target[1]. Lengsin has also been implicated as a possible genetic risk locus for major depressive disorder in a large GWAS[1]. Overall, LGSN is a lens-specific pseudo-enzyme with structural and chaperone functions essential for lens clarity, but may be co-opted as a cancer antigen or have genetic associations with neuropsychiatric conditions[1][2][3][4][5].

Other names

LengsinLGSNLGSGLULD1Glutamate-ammonia ligase domain-containing protein 1Lens glutamine synthase-likeGlutamate-ammonia ligase (glutamine synthetase) domain containing 1