What is the Amyloid Beta Precursor Protein?

November 12, 2012

The amyloid beta precursor protein is oftentimes symbolized as the APP, though it goes by various other names, as well. Some of the other names used for this gene and its products include the following:

- A4_HUMAN – A4 – AAA – ABPP – ABETA – AD1 – APPI

- Amyloid Beta Peptide

- Amyloid A4 Protein Precursor

- Amyloid of Alzheimer Disease and Aging

- Amyloid Precursor Protein

– CVAP – Cerebral Vascular Amyloid Peptide

- PreA4 – Protease Nexin-II – Protease Nexin 2 – PN-II

What Does This Gene Do?

In a nutshell, the APP gene gives instructions on how to make an amyloid precursor protein, which can be found in a lot of organs and tissues, such as the spine and the brain. Though people don’t know a lot about this protein’s functions yet, researchers claim that it might bind with other proteins on cell surfaces to help various cells connect to each other.

This protein then gets cut by enzymes in order to produce tinier fragments that can be sent out of the cell. Some of these fragments are the amyloid beta peptide and the soluble amyloid precursor protein. Recent studies seem to show that the latter can promote growth and help form nerve cells inside the brain before birth and after birth.

What Does This Have to Do with Health?

Well, Alzheimer’s disease, for one, is actually caused by different APP gene mutations. However, these mutations may also lead to other brain abnormalities, such as hereditary cerebral hemorrhage.

Alzheimer’s Disease

The amyloid beta precursor protein has at least 25 different mutations that can cause an early onset of Alzheimer’s disease. In fact, these mutations can be held responsible for up to 15% of the disorder’s early onset cases. There is one very common APP mutation, though, that changes a single amino acid with another amino acid, thus leading to the production of more APP that is stickier and longer in form. Once these fragments of protein get sent out of the cell, they might accumulate inside the brain and create amyloid plaque clumps found in Alzheimer’s disease. Then, if these toxic plaques build up too much, the neurons might start to die out and the progressive symptoms and signs of Alzheimer’s disease will start to become more evident.

Hereditary Cerebral Hemorrhage

This disorder usually happens during mid-adulthood and comes with recurring hemorrhagic strokes that could result in memory, judgement and concentration deterioration. The mutation that brings about hereditary cerebral hemorrhage may also result in amyloid beta plaque formation inside the brain tissues and the blood vessel walls that serve them.