poly(A) binding protein nuclear 1
The PABPN1 gene provides instructions for making a protein that is active (expressed) throughout the body. In cells, the PABPN1 protein plays an important role in processing molecules called messenger RNAs (mRNAs), which serve as genetic blueprints for making proteins. The PABPN1 protein attaches (binds) to the end of an mRNA molecule at a region called the polyadenine tail or poly(A) tail. Poly(A) tails consist of many adenine molecules, one of the building blocks of RNA and its chemical cousin, DNA. Poly(A) tails are needed to protect the mRNA from being broken down and allow the mRNA to move within cells. The PABPN1 protein helps add adenines to the poly(A) tail through a process called polyadenylation. The PABPN1 protein may also be involved in regulating mRNA production.
The PABPN1 protein contains an area where the protein building block (amino acid) alanine is repeated 10 times. This stretch of alanines is known as a polyalanine tract. The role of the polyalanine tract in normal PABPN1 protein function is unknown.
At least 10 different mutations in the PABPN1 gene have been found to cause oculopharyngeal muscular dystrophy. All of these mutations result in a PABPN1 protein with an expanded polyalanine tract that is 11 to 17 alanines long. The extra alanines cause the PABPN1 protein to form clumps within muscle cells that are thought to impair the normal functioning of muscle cells and eventually cause cell death. The progressive loss of muscle cells most likely causes the muscle weakness seen in people with oculopharyngeal muscular dystrophy.
- poly(A) binding protein 2
- poly(A) binding protein II
- poly(A) binding protein, nuclear 1