Chapter 6

Cell Signaling

Bacterial Signaling
Overview At times, a group of bacteria behaves like a community. To achieve this, they engage in quorum sensing, the perception of higher cell…
Yeast Signaling
6.2: Yeast Signaling
Overview Yeasts are single-celled organisms, but unlike bacteria, they are eukaryotes—cells that have a nucleus. Cell signaling in yeast is…
Contact-dependent Signaling
6.3: Contact-dependent Signaling
Contact-dependent signaling uses specialized cytoplasmic channels between cells that allow the flow of small molecules between them. In animal cells,…
Paracrine Signaling
6.4: Paracrine Signaling
Overview Paracrine signaling allows cells to communicate with their immediate neighbors via secretion of signaling molecules. The signal only…
Synaptic Signaling
6.5: Synaptic Signaling
Neurons communicate at synapses, or junctions, to excite or inhibit the activity of other neurons or target cells, such as muscles. Synapses may be…
G-protein Coupled Receptors
6.6: G-protein Coupled Receptors
G-protein coupled receptors are ligand binding receptors that indirectly affect changes in the cell. The actual receptor is a single polypeptide that…
Endocrine Signaling
6.7: Endocrine Signaling
Endocrine cells produce hormones to communicate with remote target cells found in other organs. The hormone reaches these distant areas using the…
What are Second Messengers?
6.8: What are Second Messengers?
Because many receptor binding ligands are hydrophilic, they do not cross the cell membrane and thus their message must be relayed to a second…
Intracellular Signaling Cascades
6.9: Intracellular Signaling Cascades
Intracellular signaling cascades amplify a signal originating extracellularly and directs it to its intended intracellular target resulting in…
Ion Channels
6.10: Ion Channels
Ion channels maintain the membrane potential of a cell. For most cells, especially excitable ones, the inside has a more negative charge than the…
Enzyme-linked Receptors
6.11: Enzyme-linked Receptors
Enzyme-linked receptors are proteins which act as both receptor and enzyme, activating multiple intracellular signals. This is a large group of…
Medicine: Screening Bioactive Nanoparticles
6.13: Medicine: Screening Bioactive Nanoparticles
Immune system toll-like receptors (TLR) initiate a defense system against pathogens, but when overactive, contribute to inflammation in chronic…
Immunology and Infection: Real-time Live Imaging of T-cell Signaling Complex Formation
6.14: Immunology and Infection: Real-time Live Imaging of T-cell Signaling Complex Formation
T-lymphocytes regulate the responses of the immune system against infectious diseases through a cascade triggered by receptor binding of…
Biology: Identification of Intracellular Signaling Events
6.15: Biology: Identification of Intracellular Signaling Events
Survival, proliferation, growth, and differentiation are among the many functions modulated by regulated cell death, or apoptosis. This protocol…