INTRODUCTION:
In this lecture, we will study about cell signaling and signal transduction.
Each cell in a multicellular animal is bombarded with chemical signals that are made by other cells and this is how communication occurs at cells level by different signaling molecule. Signals that regulate cell metabolism, alter or maintain its differentiated state, determine whether it should divide, and dictate whether it will live or die. The word “signals” in this context refers to nothing more than chemical molecules that are floating around the cells. In general, these signals bind to cell-surface receptors that activate several intracellular signaling pathways, so that the intracellular signals generated from different receptors will interact with one another in complex ways. Cell signaling affects virtually every aspect of cell structure and function. Cell signaling is also intimately involved in the regulation of cell growth and division. This makes the study of cell signaling crucially important for understanding how a cell can lose the ability to control cell division and develop into a malignant tumor.
The signal transduction is used to refer to a broad area of cellular biology research involving topics such as the chemical …show more content…
This property distinguishes them from small, monomeric G proteins. The guanine nucleotide-binding site is present on the G subunit. Replacement of GDP by GTP, following interaction with an activated GPCR, results in a conformational change in the G subunit. In its GTP-bound conformation, the G subunit has a low affinity for G, leading to its dissociation from the complex. Each dissociated G subunit (with GTP attached) is free to activate an effector protein, such as adenyl cyclase as shown in the figure. In this case, activation of the effector leads to the production of the second messenger