PBK - PDZ Binding Kinase | Elisa - Clia - Antibody - Protein

Background

PDZ Binding Kinase (PBK), also known as T-LAK cell-originated protein kinase (TOPK), is a serine/threonine kinase that is part of the MAPKK-like kinase family. PBK/TOPK is encoded by the PBK gene and is highly expressed in proliferative cells, particularly during mitosis. It is involved in cell cycle regulation, cellular proliferation, and has been implicated in various cancer types, making it a subject of interest for cancer research. PBK is regulated by phosphorylation and its activity is often linked to the MAPK signaling pathway. It was initially identified for its ability to interact with the PDZ domain-containing protein hDlg, which is involved in maintaining cell polarity and adhesion.

Protein Structure

The structure of PBK includes several key features:

• N-terminal Kinase Domain: This domain is responsible for its kinase activity, enabling the phosphorylation of substrate proteins.
• C-terminal PDZ-binding Motif: This motif allows PBK to interact with PDZ domain-containing proteins, crucial for its localization and function.
• Phosphorylation Sites: PBK contains specific sites that are phosphorylated by upstream kinases, regulating its activity and stability.

Classification and Subtypes

PBK belongs to the MAPKK-like kinase family, which consists of kinases involved in various signaling pathways, primarily related to cell growth, differentiation, and stress responses. Unlike other MAPKK family members, PBK is unique in its dual role in both cell cycle regulation and immune response modulation.

Function and Biological Significance

PBK plays several crucial roles in cellular processes:

• Cell Cycle Regulation: PBK is particularly active during the G2/M phase of the cell cycle, where it helps facilitate the transition from G2 to mitosis.
• Cell Proliferation: By promoting cell division, PBK is essential for the proliferation of cells, especially in rapidly dividing tissues and tumors.
• Signal Transduction: PBK is involved in the MAPK signaling pathway, influencing various downstream effects related to cell survival, proliferation, and apoptosis.
• Immune Response: PBK has been implicated in the immune response, particularly in T-cell activation and function.

Clinical Issues

• Cancer: PBK is overexpressed in several cancers, including lung, breast, colorectal, and prostate cancers. Its overexpression is often associated with poor prognosis and increased tumor aggressiveness.
• Therapeutic Target: Due to its role in cancer cell proliferation, PBK is considered a potential therapeutic target. Inhibitors of PBK are being explored as possible treatments for PBK-overexpressing tumors.
• Biomarker: PBK expression levels can serve as a biomarker for cancer diagnosis and prognosis, helping to identify aggressive forms of cancer and tailor treatment strategies.

Summary

PDZ Binding Kinase (PBK) is a serine/threonine kinase involved in regulating the cell cycle, particularly during mitosis, and plays a significant role in cellular proliferation and signaling. Its overexpression in various cancers makes it a promising target for therapeutic intervention and a potential biomarker for cancer prognosis. Understanding the molecular mechanisms of PBK and its interactions with other cellular proteins is crucial for developing targeted therapies and improving cancer treatment outcomes.