Despite the protective membrane that separates a cell from the environment, cells need the ability to detect and respond to environmental changes.…

At times, a group of bacteria behaves like a community. To achieve this, they engage in quorum sensing, the perception of higher cell density that…

Yeasts are single-celled organisms, but unlike bacteria, they are eukaryotes—cells that have a nucleus. Cell signaling in yeast is similar to…

Contact-dependent signaling uses specialized cytoplasmic channels between cells that allow the flow of small molecules between them. In animal cells,…

Secreted signals can act on a variety of target cells. In some cases, the cell that secretes a signal also detects and responds to the signaling…

Paracrine signaling allows cells to communicate with their immediate neighbors via secretion of signaling molecules. The signal only triggers a…

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 are ligand binding receptors that indirectly affect changes in the cell. The actual receptor is a single polypeptide that…

Many cellular signals are hydrophilic and therefore cannot pass through the plasma membrane. However, small or hydrophobic signaling molecules can…

Endocrine cells produce hormones to communicate with remote target cells found in other organs. The hormone reaches these distant areas using the…

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 amplify a signal originating extracellularly and directs it to its intended intracellular target resulting in…

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 are proteins which act as both receptor and enzyme, activating multiple intracellular signals. This is a large group of…

Pharmacological regulation of Toll-like receptor (TLR) responses holds great promise in the treatment of many inflammatory diseases. However, there…

Protection against infectious diseases is mediated by the immune system 1,2. T lymphocytes are the master coordinators of the immune system,…

Cells dying by apoptosis, also referred to as regulated cell death, acquire multiple new activities that enable them to influence the function of…