Claspin functions in cell homeostasis—A link to cancer?

• Published in: DNA repair Vol. 59; pp. 27 - 33
• Main Authors: Azenha, Diana, Lopes, Maria Celeste, Martins, Teresa C.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01-11-2017
• Subjects: Adaptor Proteins, Signal Transducing - metabolism; Adaptor Proteins, Signal Transducing - physiology; Apoptosis; Cancer; Cell Cycle Checkpoints; Claspin; DNA Damage; DNA Repair; DNA Replication; Genomic Instability; Homeostasis; Humans; Neoplasms - genetics; Neoplasms - metabolism; Neoplasms - physiopathology; Signal Transduction; Cell cycle checkpoints; Claspin; Genomic instability; Cancer
• ISSN: 1568-7864; 1568-7856
• DOI: 10.1016/j.dnarep.2017.09.002

•Claspin is a pivotal cell cycle checkpoint protein.•Claspin has an important role in the maintenance of genomic integrity.•Regulation of Claspin’s levels determines the cell response to stressful events.•Claspin inactivation may be an important event in carcinogenesis.•Due to its functions, Claspin is an attractive therapeutic target in cancer.
Cancer remains one of the leading causes of mortality worldwide. Most cancers present high degrees of genomic instability. DNA damage and replication checkpoints function as barriers to halt cell cycle progression until damage is resolved, preventing the perpetuation of errors. Activation of these checkpoints is critically dependent on Claspin, an adaptor protein that mediates the phosphorylation of the effector kinase Chk1 by ATR. However, Claspin also performs other roles related to the protection and maintenance of cell and genome integrity. For instance, following DNA damage and checkpoint activation, Claspin bridges checkpoint responses to DNA repair or to apoptosis. During DNA replication, Claspin acts a sensor and couples DNA unwinding to strand polymerization, and may also indirectly regulate replication initiation at firing origins. As Claspin participates in several processes that are vital to maintenance of cell homeostasis, its function is tightly regulated at multiple levels. Nevertheless, little is known about its role in cancer. Accumulating evidence suggests that Claspin inactivation could be an essential event during carcinogenesis, indicating that Claspin may function as a tumour suppressor. In this review, we will examine the functions of Claspin and how its deregulation may contribute to cancer initiation and progression. To conclude, we will discuss means by which Claspin can be targeted for cancer therapy.