PKD2 gene
The PKD2 gene provides instructions for making the polycystin-2 protein, which plays a critical role in kidney function and the regulation of cell growth.
Overview
The PKD2 gene provides instructions for making a protein called polycystin-2. This protein is found in the kidneys before birth and in many adult tissues. Although its exact function is not well understood, polycystin-2 can be regulated by a larger, somewhat similar protein called polycystin-1.
Normal Function
Polycystin-2 likely functions as a channel spanning the cell membrane of kidney cells. In conjunction with polycystin-1, the channel transports positively charged atoms (ions), particularly calcium ions, into the cell. This influx of calcium ions triggers a cascade of chemical reactions inside the cell that may instruct the cell to undergo certain changes, such as maturing to take on specialized functions. Polycystin-1 and polycystin-2 likely work together to help regulate cell growth and division (proliferation), cell movement (migration), and interactions with other cells.
Polycystin-2 is also active in other parts of the cell, including cellular structures called primary cilia. These are tiny, fingerlike projections that line the small tubes where urine is formed (renal tubules). Researchers believe that primary cilia sense the movement of fluid through these tubules, which appears to help maintain the tubules' size and structure. The interaction of polycystin-1 and polycystin-2 in renal tubules promotes the normal development and function of the kidneys.
Health Conditions Related to Genetic Changes
Polycystic kidney disease
More than 75 mutations in the PKD2 gene have been identified in people with polycystic kidney disease. These mutations are responsible for about 15 percent of all cases of autosomal dominant polycystic kidney disease (ADPKD), which is the most common type of this disorder.
- Mutation types: Mutations include changes in single DNA building blocks (base pairs) and deletions or insertions of a small number of base pairs in the gene.
- Protein impact: Most PKD2 mutations are predicted to result in the production of an abnormally small, nonfunctional version of the polycystin-2 protein.
- Disease mechanism: While the exact process is under study, the lack of polycystin-2 likely disrupts its interaction with polycystin-1 and alters signaling within the cell and in primary cilia. This causes cells lining the renal tubules to grow and divide abnormally, leading to the growth of numerous cysts.
Other Names for This Gene
- APKD2
- Pc-2
- PC2
- PKD2_HUMAN
- PKD4
- polycystic kidney disease 2 (autosomal dominant)
- polycystin-2
- TRPP2
