a transmembrane protein containing three extracellular CUB domains involved in cell adhesion and cell matrix association. May play a role in the regulation of anchorage versus migration or proliferation versus differentiation depending upon its phosphorylation status. Interacts with N- and P-cadherin, syndecans 1 and 4, the serine protease ST14, SRC and PKCG. Highly expressed in mitotic cells with low expression during interphase. Detected at highest levels in skeletal muscle and colon with lower levels in kidney, small intestine, placenta and lung. Up-regulated in a number of human tumor cell lines, as well as in colorectal cancer, breast carcinoma and lung cancer. Its expression level is correlated with the metastatic ability of carcinoma cells. May be a novel marker for leukemia diagnosis and for immature hematopoietic stem cell subsets. Belongs to the tetraspanin web involved in tumor progression and metastasis. Also expressed in cells with phenotypes reminiscent of mesenchymal stem cells and neural stem cells. Three alternatively spliced human isoforms have been reported. Isoform 1 is a single-pass membrane protein that may also be shed, giving rise to a soluble peptide. Isoform 3 is secreted. Note: This description may include information from UniProtKB.
Protein type: Cell surface; Membrane protein, integral