Plakophilin-3

Plakophilin-3 (PKP3) is a protein that in humans is encoded by the PKP3 gene. It is a member of the plakophilin family, which belongs to the armadillo repeat protein family. Plakophilins are critical for the proper function of desmosomes, which are cell structures specialized for cell-to-cell adhesion, ensuring the mechanical integrity of tissues. PKP3 is involved in the regulation of cell adhesion, cell signaling, and the establishment of epithelial cell polarity.

Function

Plakophilin-3 is predominantly found in the cytoplasm and at the cell membrane, where it plays a crucial role in the formation and maintenance of desmosomes. Desmosomes are essential for the adhesive strength between cells in many tissues, including skin, heart muscle, and epithelial cells of various organs. By interacting with other desmosomal proteins, such as desmogleins and desmocollins, PKP3 contributes to the structural integrity and durability of tissues.

In addition to its structural role, PKP3 is involved in signaling pathways that regulate cell proliferation, differentiation, and survival. It has been implicated in the Wnt signaling pathway, which is important for cell fate determination and embryonic development. PKP3's role in these pathways suggests it may also be involved in the pathogenesis of certain diseases, including cancer.

Clinical Significance

Alterations in the expression or function of PKP3 have been associated with various pathological conditions. Overexpression of PKP3 has been observed in some types of cancer, such as breast cancer and oral squamous cell carcinoma, where it may contribute to tumor progression and metastasis. Conversely, loss of PKP3 expression has been linked to the development of other cancers, indicating its potential role as a tumor suppressor in certain contexts.

Given its involvement in cell adhesion and signaling, PKP3 is also considered a potential target for therapeutic interventions in diseases characterized by abnormal cell proliferation and adhesion, including certain skin disorders and cancers.

Genetics

The PKP3 gene is located on human chromosome 11q23.3. It consists of multiple exons that encode the various domains of the plakophilin-3 protein, including the armadillo repeat domain, which is characteristic of this protein family and is critical for its function in cell-cell adhesion and signaling.

See Also

• Plakophilin
• Desmosome
• Cell adhesion
• Wnt signaling pathway