Proto-oncogene tyrosine-protein kinase Yes, also known as Proto-oncogene c-Yes, p61-Yes and YES1, is a cytoplasm protein which belongs to the protein kinase superfamily, Tyr protein kinase family and SRC subfamily. YES1 / c-Yes contains one protein kinase domain, one SH2 domain and one SH3 domain. It is thought that the subcellular distribution of Src-family tyrosine kinases, including c-Yes binding to the cellular membrane, is membranous and/or cytoplasmic. YES1 / c-Yes protein tyrosine kinase is known to be related to malignant transformation. YES1 / c-Yes and c-Src are the two most closely related members of the Src family of nonreceptor tyrosine kinases. Although there is much evidence to support redundancy in signaling between these two kinases. YES1 / c-Yes promotes formation of the tight junction by phosphorylating occludin, while c-Src signaling downregulates occludin formation in a Raf-1 dependent manner. YES1 / c-Yes has tyrosine kinase activity. It promotes infectivity of Neisseria gonorrhoeae in epithelial cells by phosphorylating MCP / CD46.