A bioinformatical approach suggests the function of the autoimmune hepatitis target antigen soluble liver antigen/liver pancreas

Selenoproteins: Molecular Pathways and Physiological Roles

“…This protein was reported to form a complex with other proteins involved in the Sec insertion (373), being consistent with its SecS function (6,133,169,319 (368), patient mutations in SecS have a less dramatic phenotype. Based on the SecS structure, these mutations are expected to disrupt protein folding and catalytic activity of SecS.…”

“…[Ser]Sec in cell extracts from patients with an autoimmune chronic hepatitis (209), and belongs to a family of PLP-dependent enzymes that is distinct from that of bacterial SecS (169). This protein was reported to form a complex with other proteins involved in the Sec insertion (373), being consistent with its SecS function (6,133,169,319 (368), patient mutations in SecS have a less dramatic phenotype.…”

How an obscure archaeal gene inspired the discovery of selenocysteine biosynthesis in humans

“…Although by the year 2000, the cDNA sequence of SLA/LP was available (38,39), workers in the field could only conclude that SLA/LP might be the Sec-tRNA synthase, a human analog of the translation factor SelB, or perhaps a seleniumtRNA protecting factor (37)(38)(39). In the following year, using a fold recognition algorithm, a bioinformatics analysis was able to correctly classify SLA/LP as a PLP-dependent enzyme and the group predicted its involvement in Sec-tRNA synthesis (40).…”

New Developments in Selenium Biochemistry: Selenocysteine Biosynthesis in Eukaryotes and Archaea

“…This additional protein had previously been detected in patients with autoimmune chronic hepatitis as an autoimmune factor that co-precipitated tRNA [Ser]Sec in cell extracts of these individuals and was known as the SLA [19]. SLA, which is a PLPdependent transferase [20], also bound other protein components involved with Sec metabolism [22,23]. We found that SLA occurred in all eukaryotes and archaea-encoding selenoproteins, but not in those organisms examined that lacked selenoproteins.…”

“…In addition, because no sequences with homology to SelA could be detected in eukaryotes, there was some question as to the identity of the Sec synthase (SecS) in mammals. The soluble liver antigen (SLA), which was initially identified as a 48-kDa protein bound to Sec tRNA [Ser]Sec and was targeted by antibodies in patients with an autoimmune chronic hepatitis [19], was reported to occur as a separate family within a larger superfamily of diverse PLP-dependent transferases [20] and proposed as a possible SecS in mammals [3,[20][21][22]. SLA was also found to exist in a protein complex with other factors involved in Sec biosynthesis and/or its insertion into protein providing further evidence that this protein is involved in selenium metabolism [22,23].…”