Cellular Signaling
sending and receiving molecular messages
Cells are in constant communication, deciding when to grow, whether dangers are present, and whether they should move to new environments. They talk to one another by sending small messenger molecules, which are received by receptor molecules on their cell surfaces. Atomic structures have revealed both these signaling molecules and their receptors.
Molecule of the Month Articles (51)
 | Acetylcholine Receptor The neurotransmitter acetylcholine opens a protein channel, stimulating muscle contraction |
 | Acetylcholinesterase Acetylcholinesterase stops the signal between a nerve cell and a muscle cell |
 | Adenylyl Cyclase Adenylyl cyclase creates second messengers to amplify signals from G-protein coupled receptors |
 | Adrenergic Receptors Adrenaline stimulates a G-protein-coupled receptor, priming us for action |
 | AMPA Receptor Receptors for the neurotransmitter glutamate in our brain come in several shapes and sizes. |
 | Anabolic Steroids Anabolic steroids like testosterone are among the most common performance enhancing drugs |
 | Auxin and TIR1 Ubiquitin Ligase The plant hormone auxin controls growth and response to light and gravity |
 | Calcium Pump Atomic structures have captured the calcium pump in action |
 | Calmodulin Calcium ions rapidly deliver signals to control processes such as muscle contraction, nerve signaling, and fertilization |
 | cAMP-dependent Protein Kinase (PKA) PKA delivers cellular signals by adding phosphates to proteins |
 | Capsaicin Receptor TRPV1 TRPV1 is an ion channel that senses heat and contributes to pain sensation. |
 | Cyclin and Cyclin-dependent Kinase Cyclins and cyclin-dependent kinases control when cells divide, making them important targets for cancer therapy. |
 | Cyclooxygenase Aspirin attacks an important enzyme in pain signaling and blood clotting |
 | Designer Insulins Engineered insulins have been developed to improve treatment of diabetes |
 | Dipeptidyl Peptidase 4 Inhibitors of dipeptidyl peptidase 4 are used to treat type-2 diabetes |
 | Epidermal Growth Factor EGF is part of a family of proteins that controls aspects of cell growth and development |
 | Estrogen Receptor Estrogen binds to receptors in the nucleus and affects key genes in development |
 | G Proteins G proteins receive signals from cellular receptors and deliver them inside the cell |
 | Glucagon Glucagon triggers the release of glucose into the blood, to power cells throughout the body |
 | Glucocorticoid Receptor and Dexamethasone An anti-inflammatory drug has given us a new way to fight the COVID-19 pandemic. |
 | Glutamate-gated Chloride Receptors The antibiotic ivermectin attacks glutamate-gated chloride channels, paralyzing parasitic worms. |
 | Growth Hormone Growth hormone brings together two copies of its cellular receptor |
 | HER2/neu and Trastuzumab Trastuzumab monoclonal antibodies targeting HER2 receptors are at the forefront of breast cancer treatment |
 | Insulin The hormone insulin helps control the level of glucose in the blood |
 | Insulin Receptor The cellular receptor for insulin helps control the utilization of glucose by cells |
 | Interferons Interferons mobilize defenses against viral infection |
 | Leptin Problems with the appetite-controlling hormone leptin can lead to obesity |
 | Mechanosensitive Channels Pressure-sensitive channels open when the internal pressure of a cell gets too high |
 | Neurotransmitter Transporters Neurotransmitters are transported out of nerve synapses to end a signal transmission |
 | Neurotrophins Neurotrophins guide the development of the nervous system |
 | Nicotine, Cancer, and Addiction Nicotine causes addiction by interacting with receptors in the brain |
 | Nitric Oxide Synthase Nitric oxide gas is used as a rapid-acting hormone and as a powerful defense |
 | Opioid Receptors Morphine and other opioid drugs bind to receptors in the nervous system, controlling pain |
 | PD-1 (Programmed Cell Death Protein 1) PD-1 and its ligands are a new target for cancer therapy |
 | Photoactive Yellow Protein Researchers use synchrotrons and X-ray lasers to reveal the rapid processes of light sensing. |
 | Phototropin Phototrophins sense the level of blue light, allowing plants to respond to changing environmental conditions |
 | Phytosulfokine Receptor Phytosulfokine and other small peptides deliver signals about growth and development in plants. |
 | Piezo1 Mechanosensitive Channel Mechanosensitive ion channels give our cells a sense of touch. |
 | Potassium Channels Potassium channels allow potassium ions to pass, but block smaller sodium ions |
 | RAF Protein Kinases A single mutation in a RAF protein kinase can help transform a normal cell into a cancer cell. |
 | Ras Protein Mutation of the growth-contolling ras protein can lead to cancer |
 | Receptor for Advanced Glycation End Products RAGE recognizes sugar-modified proteins, contributing to an inflammatory response that plays a role in diabetes |
 | Rhodopsin In our eyes, rhodopsin uses the molecule retinal to see light |
 | Serotonin Receptor Serotonin receptors control mood, emotion, and many other behaviors, and are targets for many important drugs |
 | SNARE Proteins SNARE proteins power the fusion of vesicles with membranes by forming a bundle of alpha helices |
 | Src Tyrosine Kinase Growth signaling proteins play an important role in the development of cancer |
 | Tissue Factor Tissue factor senses damage to the body and triggers formation of a blood clot |
 | Two-component Systems Bacteria respond to their environment with two-component sensing systems. |
 | Vascular Endothelial Growth Factor (VegF) and Angiogenesis VegF promotes blood vessel formation (angiogenesis), affecting cancer proliferation, wound healing, and other bodily processes. |
 | Vitamin D Receptor Vitamin D helps regulate the use of calcium throughout the body |
 | Voltage-gated Sodium Channels Voltage-gated sodium channels transmit signals in a wave through the nervous system. |
Learning Resources (12)
 | G Protein-Coupled Receptor (GPCR) Paper Model GPCRs are a large family of membrane-embedded receptors, with structural features that have been preserved through the course of evolution. This model represents the shared structural features of all GPCRs. With the extracellular N-terminus, the protein chain folds to form a bundle of seven transmembrane alpha helices connected by 3 intracellular and 3 extracellular loops with the C-terminus reaching inside the cell. |
 | Insulin Paper Model Learn about insulin, a peptide hormone that plays a critical role in our ability to use glucose from the food that we eat |
 | Award-winning Illustration of Glutamatergic Synapse Poster Molecular view of glutamatergic synapse by RCSB PDB's Maria Voigt was selected as a national finalist in the 2021 Wiki Science Competition in the United States. |
 | Glucagon-like Peptide-1 and Diabetes Poster Image of GLP-1 receptor recognizing a GLP-1 analog (yellow) with liraglutide. |
 | G-Protein Coupled Receptors Flyer In honor of the 2012 Nobel Prize in Chemistry. |
 | Insulin and Diabetes Poster Structural biology has revealed the details of insulin signaling and how this knowledge is being used to create new and better treatments for diabetes. |
 | Photoactive Yellow Protein and XFEL/SFX GIF Structures of photoactive yellow protein were determined by serial femtosecond crystallography after illumination, capturing the isomerization of the chromophore after it absorbs light. Structures included in this movie include: 5hd3 (ground state), 5hdc (100-400 femtoseconds after illumination), 5hdd (800-1200 femtoseconds), 5hds (3 picoseconds), 4b9o (100 picoseconds), 5hd5 (200 nanoseconds) and 1ts0 (1 millisecond). For more, see the Molecule of the Month on Photoactive Yellow Protein and Guide to Understanding PDB Data: Methods for Determining Atomic Structures |
 | Opioids and Pain Signaling Video Pain is one of the most trying experiences of life. On the cellular level it is communicated via special neuronal pathways. On the molecular level, however, pain is communicated like any other sensation, via a set of electrical and chemical signals facilitated by complex molecular machinery. These signals can be modulated by opioids, causing us to feel less pain, or no pain at all. Learn how opioids activate the G-proteins which in turn interact with other proteins to edit the pain signal. |
 | Neuronal Signaling and Sodium-Potassium Pump Video Explore the concepts of resting and action potentials and the role of sodium-potassium pump in regulating them. |
 | Calcium Pump Video The calcium pump moves ions across cell membranes allowing the synchronized contraction of muscle cells.
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 | 2021 Molecular Mechanisms of Drugs for Mental Disorders Video |
 | 2020 Molecular Mechanisms of Opioid Action Video |
Curriculum Resources (1)
Structural Biology Highlights (15)
Global Health (1)
 | Diabetes Mellitus - Insulin Receptor This is a membrane receptor that binds insulin and triggers a signaling cascade inside the cell, leading to glucose uptake and various other metabolic and growth-related functions. |
Goodsell Molecular Landscapes (2)
 | Insulin Action Insulin Action (2016) by David S. Goodsell. |
 | Vascular Endothelial Growth Factor (VegF) Signaling Cross section of two cells showing the VegF signaling pathway and some of its consequences. |
