Endoplasmic reticulum palmitoyl acyltransferase that mediates palmitoylation of proteins such as AMFR, CALX, ITPR1 and TFRC (PubMed:22314232, PubMed:22728137, PubMed:25368151, PubMed:28826475). Palmitoylates calnexin (CALX), which is required for its association with the ribosome-translocon complex and efficient folding of glycosylated proteins (PubMed:22314232). Mediates palmitoylation of AMFR, promoting AMFR distribution to the peripheral endoplasmic reticulum (PubMed:22728137). Together with SELENOK, palmitoylates ITPR1 in immune cells, leading to regulate ITPR1 stability and function (PubMed:25368151). Stearoyltransferase that mediates stearoylation of TFRC to inhibit TFRC-mediated activation of the JNK pathway and mitochondrial fragmentation (PubMed:26214738).