What's the significance of growth factor proteins?

Growth factors are secreted biologically active molecules which affect the growth of cells. Growth factors act on specific cell surface receptors which then transmit their growth signals to other intracellular components and ultimately result in altered gene expression. The process of transmitting an external molecular signal to a cell which induces a cellular response is known as signal transduction. Growth factors enable constant communication and feedback between adjacent and distant cells, regulating cell behavior and maintaining the structure and function of tissues. Growth factors are also significant in both physiological processes and abnormal processes such as diabetic retinopathy and cancer. For example, diabetic retinopathy results from the abnormal growth of retinal blood vessels and is a primary cause of blindness. Growth factors also regulate cellular responses required for wound healing processes such as proliferation, migration, and differentiation.