This is Kathy, Usman, and my first week working on our summer research projects which all involve modifying the PathLinker algorithm. For my project, I am interested in integrating data about protein methylations related to colon adenocarcinoma from the FireBrowse database into PathLinker. Protein methylation, which is only one of many ways that cell signaling pathways can be altered in cancerous cells, can either inhibit or enhance protein-protein interactions. I intend to devise a way to use this information to change the weights of edges connected to methylated proteins to more accurately model cancerous cell signaling pathways. I am hoping this method could eventually be generalized so that the algorithm could be modified for multiple types of cancerous mutations. I believe that this work could be important in identifying important proteins for further research.

So far, we have mostly been trying to learn about pathway reconstruction methods before we dive in. To do this, we have been re-reading the original PathLinker paper as well as a more recent paper about an alteration to PathLinker that allows it to integrate protein localization information.

We have also been working on understanding and implementing two algorithms that calculate the shortest path from a source to a target in a graph: Breadth First Search and Dijkstra’s algorithm. Breadth-first search is an algorithm that finds the path with the fewest number of edges from a source to a target. Dijkstra is more advanced and relative to our work because it takes the weight of the edges between nodes into account. Dijkstra will find the path with the lowest sum of edge weights from the source to any node in the graph.

This weekend and this coming week I have several goals. Primarily, Usman, Kathy and I need to figure out how to get the separate pieces of code that we wrote for the Dijkstra algorithm (which all work individually) to work together to first read a text file, then run Dijkstra’s algorithm, and finally produce a visual graph that shows the best paths. I need to do more research about the original PathLinker to gain a better understanding of precision-recall curves which were used to evaluate its efficacy, Ryk-CFTR-Dab2, which is a new path that was discovered in the Wnt/β-catenin signaling pathway by PathLinker, and the experimental methods that were used to verify the importance of CFTR.