MUC4
MUC4 (mucin 4, cell surface associated) is a membrane-bound, highly glycosylated mucin that helps form the mucus covering epithelial surfaces. It is also known as ASGP and MUC-4, and was previously named mucin 4, tracheobronchial. Browse Assay Genie's current range of MUC4 research reagents below, or read on for the biology behind the target.
MUC4 belongs to the mucins, a family of highly glycosylated proteins that make up the major component of mucus, the slimy and viscous secretion covering epithelial surfaces such as those in the trachea, colon and cervix. These glycoproteins protect the epithelium and are implicated in epithelial renewal and differentiation. MUC4 regulates cellular behaviour through anti-adhesive effects on cell-cell and cell-extracellular matrix interactions, and by acting as an intramembrane ligand for ERBB2.
Through ERBB2, MUC4 influences the proliferation and differentiation of epithelial cells by inducing specific phosphorylation of ERBB2. In polarised epithelial cells it segregates ERBB2 and other ERBB receptors and prevents ERBB2 from acting as a coreceptor. Interaction with ERBB2 leads to enhanced expression of CDKN1B, whereas formation of a MUC4-ERBB2-ERBB3-NRG1 complex down-regulates CDKN1B, repressing apoptosis and stimulating proliferation. The ability of MUC4 to promote tumour growth may be due mainly to repression of apoptosis rather than proliferation.
The MUC4 gene encodes an integral membrane glycoprotein found on the cell surface, although secreted isoforms may exist; UniProt lists both cell membrane and secreted locations. At least two dozen transcript variants have been described, and for many of them the full-length transcript has not been determined or they are found only in tumour tissues. The coding sequence contains a region with a variable number (more than 100) of 48 nt tandem repeats. Mouse and rat each have a Muc4 ortholog.
MUC4 is a component of the mucus that protects epithelial surfaces and is implicated in epithelial renewal and differentiation.
MUC4 acts as an intramembrane ligand for ERBB2 and can segregate ERBB receptors in polarised epithelial cells.
The MUC4-ERBB2-ERBB3-NRG1 complex down-regulates CDKN1B, repressing apoptosis and stimulating proliferation.
MUC4 may promote tumour growth mainly by repressing apoptosis, and many of its transcript variants are found only in tumour tissues.
MUC4 is a membrane-bound mucin that contributes to the mucus protecting epithelial surfaces. It has anti-adhesive effects on cell-cell and cell-matrix interactions and acts as an intramembrane ligand for ERBB2, inducing its specific phosphorylation and influencing epithelial proliferation and differentiation.
MUC4 is also known as ASGP and MUC-4, and its earlier name was mucin 4, tracheobronchial. UniProt names the protein Mucin-4. NCBI reports at least two dozen transcript variants, and secreted isoforms may exist alongside the membrane form.
Mouse and rat both have a Muc4 ortholog. MUC4 may promote tumour growth mainly through repression of apoptosis, and many of its transcript variants are found only in tumour tissues. Check the datasheet of any product for its validated reactivity.
Other mucins, including membrane-bound and gel-forming family members, with products at Assay Genie.
Gene and protein annotations from HGNC, NCBI Gene and UniProt Q99102; product specifications from Assay Genie datasheets.