Signal Transduction课件.pptVIP

Signal Transduction Hui Li, Ph.D. Laboratory of Molecular Virology, Institute of Medical Virology, Wuhan University School of Medicine Email:huilee6@ Signal transduction In biology, signal transduction refers to any process by which a cell converts one kind of signal or stimulus into another. Most processes of signal transduction involve ordered sequences of biochemical reactions inside the cell, which are carried out by enzymes, activated by second messengers, resulting in a signal transduction pathway and biological effect. Cellular Signaling pathway Video: signal transduction Signal Cells respond to their environment by reorganizing their structure, regulating the activity of proteins and altering patterns of gene expression. The stimulus for such responses is termed a signal, and may be a small molecule, a macromolecule or a physical agent, such as light… Signaling Molecules Inculde proteins, small peptides, amino acids, nucleotides, retinoids, fatty acid derivatives, and even dissolved gases such as nitric oxide (NO) and carbon monoxide (CO) etc. Extracellular Signaling Molecules Neurotransmitters are chemicals that are used to relay, amplify and modulate signals between a neuron and another cell. Hormones are chemicals released by cells that affect cells in other parts of the body. (Endocrine hormone molecules VS paracrine/autocrine hormone molecules) Chemokines are a family of small cytokines, or proteins secreted by cells (involved in pro-inflammatory response or controlling the migration of cells during normal processes of tissue maintenance or development) Question: Cells communicate in ways that resemble human communication. Decide which of the following forms of human communication are analogous to autocrine, paracrine, endocrine, and synaptic signaling by cells. A telephone conversation Talking to people at a cocktail party A radio announcement Talking to yourself Each cell type is programmed t