Abstract
Proteins make up about 15% of our body weight, are essential macromolecules to organize and mediate an array of biological processes in all forms of life. They are one of the four basic building blocks of organisms.They can be part of structural elements in a cell on a small scale, or part of the fibres that make up our muscles on a larger scale. However, proteins do a lot more than just hold things together.Interaction among the protein molecules in and outside the cells brings remarkable changes in the system.The protein-protein interactions underlie a vast number of physiological processes such as the immune response, neuronal signaling, cell motility, cell development and growth. We could realistically postulate that all the biological processes, from simple to complex, relies heavily on the network of protein-protein and protein-lipid or protein-small molecule interactions. In this book chapter, we critically focus on the protein-protein as well as protein-sphingolipid interactions in the initiation, maintenance as well as the propagation of immune cell signaling. These interactions are vital for the proper maintenance of the structure as well as function of the immune system which is essential indeed for the defence against pathogenic as well as opportunistic invading microbes into the host organism.