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A total of 10-20% of plasma membrane proteins are anchored by glycosylphosphatidylinositol (GPI). GPI is attached to proteins by GPI transamidase (GPI-T), which contains five subunits named PIGK, PIGS, PIGT, PIGU, and GPAA1. We previously reported that PIGT localizes near the nucleus in Drosophila. However, localizations of the other four subunits remain unknown. Here, we show that a catalytic subunit of GPI-T, PIGK, mainly localizes to the endoplasmic reticulum (ER), while the other four subunits localize to the nuclear envelope (NE) and ER. The NE/ER localization ratio of PIGS differs between cell types and developmental stages. Our results suggest that GPI-T catalyzes GPI attachment in the ER and the other four subunits may have other unknown functions in the NE., (© 2021 The Authors. FEBS Letters published by John Wiley & Sons Ltd on behalf of Federation of European Biochemical Societies.)

Published sequences of cDNA for human tumor necrosis factor beta (TNF-beta) have a discrepancy within the coding region as well as exon 1. To resolve these discrepancies we have re-isolated TNF-beta cDNA from the human B cell lymphoblastoid cell line, RPMI 1788, and determined its DNA sequence. Results indicate that amino acid 26 is threonine (Thr) instead of asparagine (Asn). In contrast to published sequences, the sequence of the exon 1 region corresponded to the genomic sequence of TNF-beta. From our studies we conclude that the TNF-beta gene of the human B cell lymphoblastoid cell line, RPMI 1788, is homologous with respect to the TNF-beta gene.