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Submitted by jiadam on Mon, 03/27/2017 - 23:44

Gleevec: the “wonder drug”

Gleevec is a wonder drug because in the 90s, it became one of the first drugs to be a targeted cancer cell therapy. Chemotherapy works on mutated cells as well as normal cells which is not very effective because you need normal cells to do bodily functions. Common side effects of traditional chemotherapy is fatigue, hair loss, nausea and vomiting, pain, constipation and much more. Gleevec works because research scientist in the 70s figured out what was causing the cancerous disease and in the 90s figured out what actual gene was mutated and what caused the mutated protein. The solution was to develop a small molecule inhibitor that would work to target the cancerous cells but not the normally dividing cells. Gleevec works because it inhibits Bcr-abl semi competitively by blocking the substrate binding which is ATP. If ATP is unable to bind, then the gene cannot be phosphorylated and damage the body. It also works to change the conformation of the protein which inevitable leads to a change in the catalytic activity. A huge point of emphasis in cellular and molecular biology is that the shape of the molecule affects the function and by messing with the structure and shape of the protein, it was able to work effectively in targeting cancerous cells. While Gleevec is considered a wonder drug, there are now 2nd generation inhibitors because people were becoming resistant to the drug. The resistance was caused by point mutations in the bcr-abl kinase that allowed for increased activity in bcr-abl and decreased effectiveness of the gleevec drug.

 

PP

Submitted by jiadam on Fri, 03/24/2017 - 15:53

Abl kinase

A normal abl kinase works with different signal adaptors kinases, phosphatases and cell regulators. They work in many cellular processes that control cell growth/ division as well as operate in the cell survival pathway. In addition, the abl kinase is active in oxidative stress, DNA damage repair, actin, and cell migration. Because of its overreaching ability, it is strictly regulated and this partly thorough localization. It is also regulated through intramolecular interactions and phosphorylation. This is important because if the process was not tightly regulated we would see a lot more bcr-abl translocation events. The kinase contains a nuclear import signal and nuclear export signal so that it can travel to and fro the nucleus. When abl is active in the nucleus, it signals through the DNA damage response pathways. In the cytoplasm it deals with actin dynamics and cell migration. If abl was not able to travel to the nucleus, it loses its ability to work in DNA damage response pathways.

journal

Submitted by jiadam on Fri, 03/24/2017 - 08:48

Translocation event creates Bcr-Abl

Cells have tools in place to repair DNA damage and try to fix what was disrupted. During the translocation event, the double strand breaks in DNA on 2 chromosomes. What happens is that two pieces of DNA get switched and this creates a protein that is actually function. In this situation, the N terminus of Bcr binds to the abl gene minus the N terminus portion of Abl. Because of the translocation event, Bcr now creates binding sites for other proteins. This has negative ramifications because Bcr is now interacting with more cell proliferation and survival pathways which can lead to cancerous cells. Originally, the normal abl cell contains a nuclear export signal and nuclear localization signal that allows it to move in and out of the nucleus. The Bcr-abl translocation causes the localization of the protein to be solely cytoplasmic. In addition, the bcr-abl kinase now contains a coiled coil domain which allows the abl to dimerize and autophosphorylated which activates each other. This leads to overexpression of cytoplasmic signaling activity. The bcr-abl gene loses its ability to work in DNA damage pathways and gains a hypermutation phenotype that makes mutations more likely and accumulate in different cellular pathways.

journal

Submitted by jiadam on Thu, 03/23/2017 - 20:36

Translocation event creates Bcr-Abl

Cells have tools in place to repair DNA damage and try to fix what was disrupted. During the translocation event, the double strand breaks in DNA on 2 chromosomes. What happens is that two pieces of DNA get switched and this creates a protein that is actually function. In this situation, the N terminus of Bcr binds to the abl gene minus the N terminus portion of Abl. Because of the translocation event, Bcr now creates binding sites for other proteins. This has negative ramifications because Bcr is now interacting with more cell proliferation and survival pathways which can lead to cancerous cells. Originally, the normal abl cell contains a nuclear export signal and nuclear localization signal that allows it to move in and out of the body. The Bcr-abl translocation causes the localization of the protein to be solely cytoplasmic. In addition, the bcr-abl kinase now contains a coiled coil domain which allows the abl to dimerize and autophosphorylated which activates each other. This leads to overexpression of cytoplasmic signaling activity. The bcr-abl gene loses its ability to work in DNA damage pathways and gains a hypermutation phenotype that makes mutations more likely and accumulate in different cellular pathways.

journal

Submitted by jiadam on Wed, 03/22/2017 - 13:31

JAK/Stat pathway

The JAK/Stat pathway is usually involved in cytokine signaling, cell migration, cell proliferation, apoptosis, hematopoiesis, and immune development. During the pathway,     prolactin receptors dimerize, but they are not enzyme coupled receptors. On them, there are kinases called JAKs, but they are not receptor tyrosine kinases like in other pathways, they are non-receptor tyrosine kinases. When a signal comes in, the JAKs become activated through dimerization and they autophosphorylate each other. The JAKs then phosphorylate the prolactin receptor which allows downstream proteins called STATs to bind. After the STATs bind to the phosphorylated receptor, they are phosphorylated by the JAKs. The STATs dissociate and dimerize and enter the nucleus where they are able to activate transcription  

journal

Submitted by jiadam on Tue, 03/21/2017 - 23:01

 

Survival pathway

The survival pathway in cells is to inhibit programmed cell death also known as apoptosis. When a receptor tyrosine kinase is activated and dimerized, it activates a kinases known as PI3. This interaction also has a SH2 domain which is where a target protein binds to a phosphorylated tyrosine on the receptor. Downstream proteins PDK1 and AKT bind to PIP3. The important kinase in this is the akt which is then phosphorylated by two protein kinases PK1 and PK2. Once phosphorylated, the AKT protein is released from PIP3 and enters the cytosol where it can then target BAD. BAD is a protein that sequesters Bcl2 which prevents Bcl2 from performing its function. Bcl2’s function is to prevent cell death so when BADis binding to bcl2, the cell is going to die. Akt phosphorylates BAD, Bcl2 is released and can do its function. BAD technically is inactive when phosphorylated because it can no longer perform its function of binding to bcl2 and sequestering its functional ability.

journal

Submitted by jiadam on Tue, 03/21/2017 - 10:05

Abl kinase

A normal abl kinase works with different signal adaptors kinases, phosphatases and cell regulators. They work in many cellular processes that control cell growth/ division as well as operate in the cell survival pathway. In addition, the abl kinase is active in oxidative stress, DNA damage repair, actin, and cell migration. Because of its overreaching ability, it is strictly regulated and this partly thorough localization. It is also regulated through intramolecular interactions and phosphorylation. The kinase contains a nuclear import signal and nuclear export signal so that it can travel to and fro the nucleus. When abl is active in the nucleus, it signals through the DNA damage response pathways. In the cytoplasm it deals with actin dynamics and cell migration.

Perfect paragraph

Submitted by jiadam on Sat, 03/11/2017 - 19:34

Activating receptor tyrosine kinase

Upon receiving a signal, 2 receptor tyrosine kinases come together and dimerize, Dimerization allows the receptors to phosphorylate each other which means they add a phosphate to the opposing receptor and thus activates the kinase. The phosphorylated tyrosine creates binding sites for downstream protein effectors to bind. This binding area is called an SH2 domain. RTKS are active in survival signals where the cell need a constant signal telling it to continue to survive. They are also active in growth factor signaling pathways. These pathways can tell a cell to divide more quickly and proliferate cell growth or to limit cell growth.

journal

Submitted by jiadam on Sat, 03/11/2017 - 19:13

Purpose of DNA extraction

The purpose of DNA extraction is to obtain DNA that is purified that can be used for different scientific test such as PCR and sequencing. A scientific researcher or laboratory scientist can extract DNA from a myriad of sources such as blood, semen, saliva, urine, hair, teeth, bone, tissue, fingernail clippings, and even chewing gum. When extracting DNA, the most important goals are to maximize the most amount of DNA recovery, to remove the inhibitors and nucleases, and to maximize the DNA quality. The most common DNA extraction procedures are organic extraction using phenol-chloroform, non-organic extraction using proteinase K and salting out, Chelex extraction, using FTA paper, or silica based extraction.

journal

Submitted by jiadam on Fri, 03/10/2017 - 13:52

Activating receptor tyrosine kinases

When a signal comes in, the tyrosine kinases dimerize. When they dimerize, they then can auto phosphorylate each other. This creates binding sites for downstream protein effectors to bind. This binding area is called an SH2 domain. Receptor tyrosine kinases are active in survival signals where the cell needs a constant signal telling it to continue to survive. They are also active in growth factor signaling pathways. These pathways can tell a cell to divide more quickly and proliferate cell growth or to limit cell growth.

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