Golgi membrane protein 1 (GOLM1) also known as Golgi phosphoprotein 2 or Golgi membrane protein GP73 is a

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, respo ...

that in humans is encoded by the ''GOLM1''

gene In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a ba ...

. Two alternatively spliced transcript variants encoding the same protein have been described for this gene.

Function

The

Golgi complex The Golgi apparatus (), also known as the Golgi complex, Golgi body, or simply the Golgi, is an organelle found in most eukaryotic cells. Part of the endomembrane system in the cytoplasm, it packages proteins into membrane-bound vesicles insi ...

plays a key role in the sorting and modification of proteins exported from the

endoplasmic reticulum The endoplasmic reticulum (ER) is, in essence, the transportation system of the eukaryotic cell, and has many other important functions such as protein folding. It is a type of organelle made up of two subunits – rough endoplasmic reticulum ( ...

. The protein encoded by this gene is a type II Golgi transmembrane protein. It processes protein synthesized in the rough endoplasmic reticulum and assists in the transport of protein cargo through the Golgi apparatus. The expression of this encoded protein has been observed to be upregulated in response to viral infection.

Clinical significance

Golgi membrane protein 1 is overexpressed in

prostate cancer Prostate cancer is cancer of the prostate. Prostate cancer is the second most common cancerous tumor worldwide and is the fifth leading cause of cancer-related mortality among men. The prostate is a gland in the male reproductive system that sur ...

and lung adenocarcinoma tissue. Blood levels of GP73 are higher in patients with liver cancer than in healthy individuals. In addition, levels were not significantly higher in patients with diseases other than liver disease. The current blood test used to screen for early tumors in people at high risk for liver cancer involves the

alpha-fetoprotein Alpha-fetoprotein (AFP, α-fetoprotein; also sometimes called alpha-1-fetoprotein, alpha-fetoglobulin, or alpha fetal protein) is a protein that in humans is encoded by the ''AFP'' gene. The ''AFP'' gene is located on the ''q'' arm of chromosome 4 ...

(AFP). Patients who are at risk for non-metastatic, or primary, liver cancer typically have chronic liver disease such as

cirrhosis Cirrhosis, also known as liver cirrhosis or hepatic cirrhosis, and end-stage liver disease, is the impaired liver function caused by the formation of scar tissue known as fibrosis due to damage caused by liver disease. Damage causes tissue repai ...

. Such cases of cirrhosis are usually due to infection caused by infectious hepatitis (usually hepatitis B or

hepatitis C Hepatitis C is an infectious disease caused by the hepatitis C virus (HCV) that primarily affects the liver; it is a type of viral hepatitis. During the initial infection people often have mild or no symptoms. Occasionally a fever, dark urine, a ...

, though there are other strains), or because of degenerative fatty liver disease (which can be especially severe in those with alcoholism). However, the AFP test is not usually sensitive enough to detect liver cancer in time and it often generates false positives. So far, the blood samples of more than 1,000 patients with various stages of liver and non-liver disease have been tested for the presence of GP73 in several studies. Several medical diagnostic companies are in the process of developing automated serum tests for the protein that could be performed in routine hospital laboratories.

Function

Clinical significance

References

Further reading