California State Route 125

State Route 125 (SR 125) is a state highway in the US state of California. As a freeway, it runs from Otay Mesa Road (former SR 905) in Otay Mesa near the U.S.–Mexico border to SR 52 in Santee. SR 125 serves as an additional north–south route in the San Diego metropolitan area, also connecting SR 54, SR 94, and Interstate 8 (I-8). The definition of the route continues to SR 56, but this portion has not been constructed, and there are no plans to do so.

The first parts of SR 125 were added to the state highway system in 1933, connecting Route 94 with U.S. Route 80 (US 80). In the 1964 state highway renumbering, what was signed as Route 67 was transferred to the new SR 125. After several delays in funding and in planning, the highway was extended north to SR 52 and south to SR 54 in the early 2000s.

The southern portion of SR 125 from Otay Mesa Road to SR 54 near Chula Vista is a toll road called the South Bay Expressway; this portion was completed in 2007. The toll road was operated by a public-private partnership known as South Bay Expressway LLC. However, the partnership declared bankruptcy in 2010 and sold the road to the San Diego Association of Governments (SANDAG) in 2011. Since then, following a decrease in the toll amount, traffic using the highway has increased.

CA-125

CA-125 (cancer antigen 125, carcinoma antigen 125, or carbohydrate antigen 125) also known as mucin 16 or MUC16 is a protein that in humans is encoded by the MUC16 gene. MUC16 is a member of the mucin family glycoproteins. CA-125 has found application as a tumor marker or biomarker that may be elevated in the blood of some patients with specific types of cancers, or other benign conditions.

Structure

Mucin 16 is a membrane associated mucin that possesses a single transmembrane domain. A unique property of MUC16 is its large size. MUC16 is more than twice as long as MUC1 and MUC4 and contains about 22,000 amino acids, making it the largest membrane associated mucin.

MUC16 is composed of three different domains:

The N-terminal and tandem repeat domains are both entirely extracellular and highly O-glycosylated. All mucins contain a tandem repeat domain that has repeating amino acid sequences high in serine, threonine and proline. The C-terminal domain contains multiple extracellular SEA (sea urchin sperm protein, enterokinase, and agrin) modules, a transmembrane domain, and a cytoplasmic tail. The extracellular region of MUC16 can be released from the cell surface by undergoing proteolytic cleavage. MUC16 is thought to be cleaved at a site in the SEA modules.