Wnts are secreted growth factors that have critical roles in cell fate determination and stem cell renewal. As a family of signal transduction pathways made up of proteins, they serve to pass signals to a cell through its surface receptors. The Wnt family first came to attention for their role is carcinogenesis, but were soon recognized to have a larger factor in embryonic development, too, including a role in body axis patterning, cell fate specification, cell proliferation and cell migration. As such, Wnts play a huge role in the early development of bone, heart, and muscle tissue in the embryo.
As indicated, Wnts play a key role in different functions related to the development of tissue including bone, heart, and muscle cells through the processes mentioned. As such, mutations within the Wnt pathways are linked to human birth defects, cancer and other diseases. Aberrant Wnt signaling is highly associated with numerous cancers and may be responsible for drug resistance and recurrence of tumors. Several genes involved in Wnt signaling act as oncogenes or tumor suppressor genes. The APC gene functions as a tumor suppressor, i.e., it encodes a protein that normally functions as a growth suppressor in colon epithelium. Wnt proteins function as morphogens that are capable of both short and long range signaling. It is activated by highly conserved Wnt proteins that are secreted as palmitoylated glycoproteins and act as morphogens to form a concentration gradient across a developing tissue. Different members of Wnt family function in different ways, too. Wnt proteins can also inhibit the formation of synapses. Wnts might also play a negative role at the vertebrate NMJ, with nt3a decreasing the ability of agrin to induce AChR clustering in cultured myotubes
Wnts are involved in a huge amount of processes, particularly regarding cell development within the embryos. They’ve been shown to play roles in processes as board and different as segmentation, CNS patterning, and control of asymmetric cell divisions. The transduction of Wnt signals between cells is carried out through a complicated chain of events. These events include post-translational modification and secretion of Wnts, the binding of Wnts to transmembrane receptors, activation of cytoplasmic effectors, and transcriptional regulation of target genes. Through the complicated process of signal integration and regulation, Wnt signaling has a role in many different aspects of both development and disease, such as melanoma, colorectal cancer, dementia and psychiatric diseases.
As diverse as the Wnt family is and as many processes and diseases it plays a role in, it also has a large number of interactions. The most documented of which, and the relationship that drew most attention to the genes in the first place, is the Frizzied family receptors, to which Wnt-family proteins bind to in order to pass biological signals to the Dishevelled protein inside the shell.
There are twelve Wnt genes, all falling within 12 Wnt subfamilies. All Wnt genes have a crystal structure, are around 40 kDa in size and have multiple conserved cysteines. 4KRR is one of the Wint genes with an elucidated structure that shows it as an asymmetric monomer with one unique protein chain