DAPK1

Fig1. Structure of different isoforms and functional domains of DAPK family members. Percentage gives structural similarity to the DAPK molecule. (Sara Steinmann, 2015)

What is DAPK1 protein?

DAPK1 (death associated protein kinase 1) gene is a protein coding gene which situated on the long arm of chromosome 9 at locus 9q21. Death-associated protein kinase 1 is a positive mediator of gamma-interferon induced programmed cell death. DAPK1 encodes a structurally unique calmodulin dependent serine-threonine kinase that carries 8 ankyrin repeats and 2 putative P-loop consensus sites. It is a tumor suppressor candidate. The DAPK1 protein is consisted of 1430 amino acids and its molecular mass is approximately 160.0 kDa.

What is the function of DAPK1 protein?

DAPK1 (Death Associated Protein Kinase 1) is a calcium/calmodulin-regulated serine/threonine protein kinase that plays a key role in a variety of cellular functions, particularly in programmed cell death (apoptosis), autophagy, and cell cycle regulation. DAPK1, named for its close association with apoptosis, can promote cell death by phosphorylating various substrates, including the stabilization and activation of the tumor suppressor gene p53 and the regulation of other pro-apoptotic factors. In addition, DAPK1 is involved in the process of autophagy, an intracellular breakdown and recycling mechanism that is critical for cell survival and homeostasis.

DAPK1 Related Signaling Pathway

One of the widely studied functions of DAPK1 is its pro-apoptotic effect, which can enhance cell sensitivity to apoptotic stimuli by phosphorylating and activating key apoptotic factors such as tumor protein p53 and extracellular signal-regulated kinase (ERK). DAPK1 is also involved in the regulation of autophagy, cytoskeletal reconstruction, and immune processes.

DAPK1 Related Diseases

In the cancer field, DAPK1 is considered a tumor suppressor whose loss of function or down-regulated expression has been found in a variety of malignancies, including lung, breast, colon, and liver cancers. In addition to cancer, DAPK1 has been linked to other diseases. Changes in the expression and activity of DAPK1 in neurodegenerative diseases have also attracted the attention of researchers because it may be involved in the survival and death of neurons. In terms of the immune system, the regulatory role of DAPK1 may play a role in the pathological mechanisms of autoimmune diseases and inflammatory diseases.

Bioapplications of DAPK1

Although the development of small molecule activators or inhibitors targeting DAPK1 is still in the early stages, some studies have indicated that DAPK1 activity may be strongly associated with the prognosis of multiple cancer types and, in some cases, sensitize cancer cells to chemotherapy drugs.

Case study 1: Mi-Hyeon You, 2021

The activation of metastatic reprogramming is vital for cancer metastasis, but little is known about its mechanism. This study investigated the potential role of death-associated protein kinase 1 (DAPK1) in thyroid cancer progression. This study generated knockdown (KD) DAPK1 using siRNA or shRNA in 8505C and KTC-1 cell lines, which we transiently or stably overexpressed in MDA-T32 and BCPAP cell lines. DAPK1 KD in 8505C and KTC-1 cells significantly increased cell proliferation and colony formation compared with controls. We observed significant inhibition of cancer cell invasion in cells overexpressing DAPK1, but the opposite effect in KD cells. Tumorsphere formation significantly increased after inhibition of DAPK1 expression in 8505C cells and was significantly suppressed in DAPK1-overexpressing MDA-T32 and BCPAP cells. DAPK1 overexpression inhibited mRNA and protein levels of stem markers (OCT4, Sox2, KLF4, and Nanog). Furthermore, the expression of these markers increased after KD of DAPK1 in 8505C cells. Mechanistic studies suggest that DAPK1 may modulate the expression of stem cell markers through the inhibition of β-catenin pathways.

Fig1. The expression level of DAPK1-overexpressed BCPAP cells was confirmed by Western blot.

Fig2. The expression of stem cell markers (Oct4, Sox2, and Nanog) according to the expression of DAPK1 protein in human PTC tissues was investigated.

Case study 2: Sara Steinmann, 2019

Colorectal cancer (CRC) is one of the leading cancer-related causes of death worldwide. Despite the improvement of surgical and chemotherapeutic treatments, as of yet, the disease has not been overcome due to metastasis to distant organs. The Death-associated protein kinase 1 (DAPK1), recently, has been shown to be a potential candidate for regulating metastasis in CRC. Hence, the aim of the study was to investigate the impact of DAPK1 protein on CRC aggressiveness. Using CRISPR/Cas9 technology, the researchers generated DAPK1-deficient HCT116 monoclonal cell lines and characterized their knockout phenotype in vitro and in vivo. They show that loss of DAPK1 implemented changes in growth pattern and enhanced tumor budding in vivo in the chorioallantoic membrane (CAM) model. Further, they observed more tumor cell dissemination into chicken embryo organs and increased invasion capacity using rat brain 3D in vitro model. The novel identified DAPK1-loss gene expression signature showed a stroma typical pattern and was associated with a gained ability for remodeling the extracellular matrix.

Fig3. Western Blot of DAPK1 expression status in various colorectal cancer cell lines.

Fig4. WST-8 assay of HCT116 cell and DAPK1 ko clones 7/6, 10/8 and 21/9 was conducted for quantification of the metabolic activity after pre-incubation of 0, 24 and 48 h and 2 h of WST-8 treatment.

DAPK1 has several biochemical functions, for example, ATP binding,GTP binding,calmodulin binding. Some of the functions are cooperated with other proteins, some of the functions could acted by DAPK1 itself. We selected most functions DAPK1 had, and list some proteins which have the same functions with DAPK1. You can find most of the proteins on our site.

DAPK1 has direct interactions with proteins and molecules. Those interactions were detected by several methods such as yeast two hybrid, co-IP, pull-down and so on. We selected proteins and molecules interacted with DAPK1 here. Most of them are supplied by our site. Hope this information will be useful for your research of DAPK1.

N/A;KLHL20;MAPK3