Mucin-16

Mucin-16 (MUC16) is a type of mucin, a family of high molecular weight, heavily glycosylated proteins (glycoconjugates) produced by epithelial tissues in most animals. MUC16 is a membrane-associated mucin that plays a crucial role in forming a protective mucous barrier against foreign particles and infectious agents at mucosal surfaces.

Structure

Mucin-16 is a large transmembrane protein with a unique structure. It is composed of a large extracellular domain, a single transmembrane domain, and a short cytoplasmic tail. The extracellular domain is heavily glycosylated and contains several tandem repeat regions, which are characteristic of mucins. The cytoplasmic tail interacts with several intracellular proteins, playing a role in signal transduction.

Function

MUC16 is best known for its role in the formation of a protective barrier on the ocular surface. It is the major component of the glycocalyx, a gel-like layer that covers the corneal and conjunctival epithelium. MUC16 also plays a role in cell adhesion and signaling, and it has been implicated in several diseases, including dry eye disease, ocular surface disease, and ovarian cancer.

Clinical significance

MUC16 is overexpressed in many types of cancer, including ovarian cancer, pancreatic cancer, and lung cancer. In ovarian cancer, MUC16 is cleaved and released into the bloodstream, where it can be detected as the cancer antigen 125 (CA-125). CA-125 is a well-known biomarker for ovarian cancer and is used in the diagnosis and monitoring of this disease.

See also

• Mucin
• Ovarian cancer
• Cancer antigen 125