CELE_F45E6.2, F45E6.2

atf-6 is an ortholog of mammalian ATF6alpha, a proximal sensor required for the unfolded protein response (UPR) in the endoplasmic reticulum (ER); ATF6alpha is a transmembrane protein, with a bZIP transcription factor domain in its cytosolic amino terminus that is released and activated by proteolytic cleavage upon ER stress; either ire-1 or xbp-1 deletions are synthetically lethal with atf-6 or pek-1 deletions, producing arrest in L2 larvae; RNAi of Y56A3A.2 (a S2P protease homolog) is synthetically lethal with ire-1(RNAi), consistent with the hypothesis that Y56A3A.2 cleaves ATF-6; atf-6 regulates few genes that are transcriptionally induced by UPR, but regulates roughly one-quarter of genes that require UPR constitutively; pdr-1 transcripts are strongly upregulated in a atf-6(ok551) mutant background, but atf-6(ok551);pdr-1(lg103) double mutants have a grossly normal phenotype ; atf-6 is dispensable for proper localization of GLR-1 glutamate receptors.

CELE_F40F9.2, F40F9.2

tag-120 encodes a predicted transmembrane protein; as loss of tag-120 activity via RNAi does not result in any abnormalities, the precise role of TAG-120 in C. elegans development and/or behavior is not yet known; however, TAG-120 is homologous to a Drosophila NMDA receptor-associated protein and mammalian transmembrane proteins that function in Fas-mediated cell death, so TAG-120 may play a role in neuronal functions and/or apoptosis; a tag-120 reporter fusion is expressed in the nervous system, pharyngeal muscles, and to a lesser extent in the excretory system.