Dap, short for Death-associated protein kinase, is a calcium/calmodulin-dependent serine/threonine kinase. It plays a crucial role in several cell death pathways such as apoptosis and programmed necrosis, and is also identified as an essential regulator of autophagy, a cellular self-degradation process [1]. It is associated with the cell cytoskeleton and has ankyrin repeats and a 'death' domain in its structure.

Functional studies suggest that Dap-kinase may direct autophagy specifically towards autophagic cell death. It has been mapped to distinct stages in autophagy signaling, including interactions with the Beclin-1/phosphatidylinositol 3-kinase (PI(3)K) complex necessary for autophagosome formation, and with the LC3-binding protein, MAP1B, which may regulate vesicle trafficking [1]. Also, Dap-kinase exerts apoptotic effects by suppressing integrin functions and integrin-mediated survival signals, thereby activating a p53-dependent apoptotic pathway [2]. In terms of tumor-related research, lung carcinoma clones with highly aggressive metastatic behavior did not express Dap-kinase, while restoration of Dap-kinase to physiological levels in high-metastatic Lewis carcinoma cells suppressed their ability to form lung metastases and delayed local tumor growth [3].

In conclusion, Dap plays significant roles in apoptosis, autophagy, and metastasis-related processes. The functional studies on Dap-kinase, especially those using in vivo models like the ones with Lewis carcinoma cells, contribute to understanding its role in tumor-related diseases, potentially providing new insights for cancer treatment strategies.

References:

1. Bialik, Shani, Kimchi, Adi. 2009. Lethal weapons: DAP-kinase, autophagy and cell death: DAP-kinase regulates autophagy. In Current opinion in cell biology, 22, 199-205. doi:10.1016/j.ceb.2009.11.004. https://pubmed.ncbi.nlm.nih.gov/20005690/

2. Wang, Won-Jing, Kuo, Jean-Cheng, Yao, Chung-Chen, Chen, Ruey-Hwa. 2002. DAP-kinase induces apoptosis by suppressing integrin activity and disrupting matrix survival signals. In The Journal of cell biology, 159, 169-79. doi:. https://pubmed.ncbi.nlm.nih.gov/12370243/

3. Inbal, B, Cohen, O, Polak-Charcon, S, Eisenbach, L, Kimchi, A. . DAP kinase links the control of apoptosis to metastasis. In Nature, 390, 180-4. doi:. https://pubmed.ncbi.nlm.nih.gov/9367156/