Cleft lip and palate transmembrane protein 1-like protein (CLPTM1L), also known as CRR9 (cisplatin resistance-related protein 9), is a scramblase that mediates the translocation glucosaminylphosphatidylinositol (alpha-D-GlcN-1-6-(1,2-diacyl-sn-glycero-3-phospho)-1D-myo-inositol, GlcN-PI) across the endoplasmic reticulum (ER) membrane, from the cytosolic leaflet to the luminal leaflet of the ER membrane, where it participates in the biosynthesis of glycosylphosphatidylinositol (GPI) []. This transmembrane protein is overexpressed in non-small cell lung cancer, where it protects tumour cells from genotoxic apoptosis []. It has been identified as an overexpressed protein in human ovarian tumour cell lines that are resistant to cisplatin []. CLPTM1L may protect cells from genotoxic stress induced apoptosis through regulation of Bcl-xL []. It interacts with phosphoinositide 3-kinase and is essential for Ras-induced AKT phosphorylation []. The CLPTM1L gene lies within a cancer susceptibility locus at chromosome 5p15.33 (TERT-CLPTM1L) defined by genome-wide association studies [].This entry also includes CLPTM1-like membrane protein cnrB from slime molds
This entry includes cleft lip and palate transmembrane protein 1 (CLPTM1) and cleft lip and palate transmembrane protein 1-like protein (CLPTM1L, also known as CRR9). This entry also includes uncharacterised proteins from fungi and plants. Clefts of the lip and/or palate (CL/P) are some of the most common birth defects. They may be categorised into syndromic or non-syndromic types, with syndromic defects having an underlying chromosomal or teratogenic cause. Around 70% of clefts are non-syndromic and individuals have no typical physical or developmental abnormalities; these clefts generally show polygenetic behaviour and complex inheritance []. Studies have identified regions on chromosomes 19 and 11 which may be involved in non-syndromic cleft lip and palates; this included a novel gene on chromosome 19, cleft lip and palate-associated transmembrane protein 1 (CLPTM1) []. The Poliovirus receptor-related 1 gene (PVRL1), which is located on chromosome 11, has also been shown to associate with non-syndromic cleft lip and palates [, ].Human CLPTM1L is a scramblase that mediates the translocation glucosaminylphosphatidylinositol (alpha-D-GlcN-1-6-(1,2-diacyl-sn-glycero-3-phospho)-1D-myo-inositol, GlcN-PI) across the endoplasmic reticulum (ER) membrane, from the cytosolic leaflet to the luminal leaflet of the ER membrane, where it participates in the biosynthesis of glycosylphosphatidylinositol (GPI) []. It protects non-small cell lung cancer tumour cells from genotoxic apoptosis and may contribute to lung cancer risk [, ].
