Cux1 (CUTL1, CDP, CDP/Cux) is a homeodomain protein that in humans is encoded by the CUX1 gene. [3] [4] [5] [6]
The protein encoded by this gene is a member of the homeodomain family of DNA binding proteins. It regulates gene expression, morphogenesis, and differentiation and it also plays a role in cell cycle progression, particularly at S-phase. Several alternatively spliced transcript variants of this gene have been described, but the full-length nature of some of these variants has not been determined, and the p200 isoform of Cux1 is processed proteolytically to smaller active isoforms, such as p110. [6] Cux1 DNA binding is stimulated by activation of the PAR2/F2RL1 cell-surface G-protein-coupled receptor in fibroblasts and breast-cancer epithelial cells to regulate Matrix metalloproteinase 10, Interleukin1-alpha, and Cyclo-oxygenase 2 (COX2) genes. [7]
Genetic data from over 7,600 cancer patients shows that over 1% has the deactivated CUX1 which links to progression of tumor growth. Researchers from the Wellcome Trust Sanger Institute reported that the mutation of CUX1 reduces the inhibitory effects of a biological inhibitor, PIK3IP1 (phosphoinositide-3-kinase interacting protein 1), resulted in higher activity of the growth promoting enzyme, phosphoinositide 3-kinase (PI3K) which leads to tumor progression. Although CUX1 is mutated at a lower rate compared to other known gene mutations that cause cancer, this deactivated gene is found across many cancer types in this study to be the underlying cause of the disease. [8] [9]
The CUX1 gene Alternatively Spliced Product was first reported in 1997. [11] [lower-alpha 1] The CUX1 gene has up to 33 exons. CASP mRNA includes exons 1 through 14 and 25 through 33. [13] The human CASP protein is predicted to contain 678 amino acids, of which 400 are shared with CUTL1. [11] CASP protein is approximately 80 k D. [11] It lacks the DNA binding region of CUTL1, [11] [14] but instead contains a trans-membrane domain that allows it to insert into lipid bilayers. [14] It has been localized to the Golgi apparatus. [14]
CASP has been reported to be part of a complex with Golgin 84 that tethers COPI vesicles and is important for retrograde transport in the Golgi and between the Golgi and endoplasmic reticulum. [15] The targeting of vesicles involves tethers and SNAREs. [15]
Cux1 (CUTL1, CDP, CDP/Cux) has been shown to interact with:
These physical interactions are reported in BioPlex 2.0
The TATA-binding protein (TBP) is a general transcription factor that binds specifically to a DNA sequence called the TATA box. This DNA sequence is found about 30 base pairs upstream of the transcription start site in some eukaryotic gene promoters.
POU domain, class 2, transcription factor 1 is a protein that in humans is encoded by the POU2F1 gene.
ADP-ribosylation factor-binding protein GGA1 is a protein that in humans is encoded by the GGA1 gene.
DNA replication licensing factor MCM3 is a protein that in humans is encoded by the MCM3 gene.
Nuclear transcription factor Y subunit beta is a protein that in humans is encoded by the NFYB gene.
Y box binding protein 1 also known as Y-box transcription factor or nuclease-sensitive element-binding protein 1 is a protein that in humans is encoded by the YBX1 gene.
Ran-binding protein 9 is a protein that in humans is encoded by the RANBP9 gene.
Mannose-6-phosphate receptor binding protein 1 (M6PRBP1) is a protein which in humans is encoded by the M6PRBP1 gene. Its gene product, as well as the gene itself, is commonly known as TIP47.
Nuclear transcription factor Y subunit gamma is a protein that in humans is encoded by the NFYC gene.
Homeobox protein DLX-3 is a protein that in humans is encoded by the DLX3 gene.
Paired mesoderm homeobox protein 2A is a protein that in humans is encoded by the PHOX2A gene.
CCAAT/enhancer-binding protein zeta is a protein that in humans is encoded by the CEBPZ gene.
Nuclear factor 1 C-type is a protein that in humans is encoded by the NFIC gene.
Nucleobindin-1 (NUCB1), also known as calnuc, is a protein that in humans is encoded by the NUCB1 gene.
Paired related homeobox 1 is a protein that in humans is encoded by the PRRX1 gene.
Trans-Golgi network integral membrane protein 2 is a protein that in humans is encoded by the TGOLN2 gene.
CDP-diacylglycerol—inositol 3-phosphatidyltransferase is an enzyme that in humans is encoded by the CDIPT gene.
In molecular biology, the CUT domain is a DNA-binding motif which can bind independently or in cooperation with the homeodomain, which is often found downstream of the CUT domain. Proteins display two modes of DNA binding, which hinge on the homeodomain and on the linker that separates it from the CUT domain, and two modes of transcriptional stimulation, which hinge on the homeodomain.
Giantin or Golgin subfamily B member 1 is a protein that in humans is encoded by the GOLGB1 gene. Giantin is located at the cis-medial rims of the Golgi apparatus and is part of the Golgi matrix that is responsible for membrane trafficking in secretory pathway of proteins. This function is key for proper localisation of proteins at the plasma membrane and outside the cell which is important for cell function that is dependent on for example receptors and the extracellular matrix function. Recent animal model knockout studies of GOLGB1 in mice, rat, and zebrafish have shown that phenotypes are different between species ranging from mild to severe craniofacial defects in the rodent models to just minor size defects in zebrafish. However, in adult zebrafish a tumoral calcinosis-like phenotype was observed, and in humans such phenotype has been linked to defective glycosyltransferase function.
CUX1 is an animal gene. The name stands for Cut like homeobox 1. The term "cut" derives from the "cut wing" phenotype observed in a mutant of Drosophila melanogaster. In mammals, a CCAAT-displacement activity was originally described in DNA binding assays. The human gene was identified following purification of the CCAAT-displacement protein (CDP) and has been successively been called CDP, Cut-like 1 (CUTL1), CDP/Cut and finally, CUX1.. Cut homeobox genes are present in all metazoans. In mammals, CUX1 is expressed ubiquitously in all tissues. A second gene, called CUX2, is expressed primarily in neuronal cells.
This article incorporates text from the United States National Library of Medicine, which is in the public domain.