Name: self-signaling cells in immunity and cancer
Uploaded: 2026-08-26T08:22:31.647Z
Duration: 1 min 54 s
Channel: JoVE

Multicellular organisms use four main chemical signaling pathways for communication: autocrine, paracrine, endocrine, and contact-dependent signaling.Autocrine signaling is a form of cell communication in which a cell interacts with itself.The signaling molecules involved in this process are called autocrine agents.These molecules are released into the extracellular space and bind to specific receptors on the plasma membrane of the same cell.This activates intracellular signaling pathways that relay signals from the cell surface to different parts of the cell, including the nucleus.As a result, the same cell functions as both the signaling cell and the target cell.In the nucleus, changes in gene expression regulate cellular activities such as survival, differentiation, and proliferation.Autocrine signaling plays important roles in processes such as embryonic development and inflammatory responses.For example, during an infection, activated T lymphocytes release cytokines into the extracellular environment.These cytokines then bind to receptors on the surface of the same T lymphocyte, triggering an autocrine response.This receptor binding activates intracellular signaling pathways t

autocrine signaling

Autocrine Signaling

Autocrine signaling is one of the many signaling mechanisms that function inside multicellular organisms to carry out intercellular communication. In this type of signaling mechanism, the same cell that secretes an extracellular signaling molecule also expresses the receptors to bind and respond to that signaling molecule.Autocrine Signaling in MacrophagesUnder normal physiological conditions, autocrine signaling is essential for maintaining homeostasis. This process is well characterized in the macrophages of the immune system. These cells secrete a variety of signals, such as the cytokine Interleukin-1 (IL-1), and also possess membrane receptors for IL-1. This means that, upon secretion, IL1 can bind to receptors on the macrophages and activate an intracellular signaling cascade. The resulting intracellular signals trigger the secretion of additional cytokines, including more IL-1, from the macrophages. Though IL-1 secreted by macrophages can also bind to receptors on other cell types, binding to the signaling cell is important to regulate signal production.Autocrine Signaling &amp; CancerAutocrine signaling is also a major signaling mechanism in cancer cells. Cancerous cells secrete a variety of self-sustaining growth signals that act as autocrine mediators and control cell division rates. For example, in the majority of breast cancer cases, cancer cells express progesterone receptors on their cell surface. These receptors bind to progesterone released from the cancer cells themselves, thus, acting in an autocrine manner to stimulate cell proliferation.

Autocrine signaling is one of the many signaling mechanisms that function inside multicellular organisms to carry out intercellular communication. In this ...

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Biology

Cellular Processes

Cell Signaling

KEY TERMS AND CONCEPTS

self-signaling cells in immunity and cancer

Autocrine signaling is a cell communication method in which a cell sends a signal to itself. The same cell releases an extracellular signaling molecule and also has receptors that can bind to that molecule. This lets the cell respond to its own message.

In the immune system, this process is important for homeostasis, or keeping body conditions stable. A well-studied example is the macrophage, an immune cell that secretes cytokines such as interleukin-1, or IL-1. Macrophages also have membrane receptors for IL-1, so the released IL-1 can bind back to the same cell and start an intracellular signaling cascade.

That internal signal can trigger the macrophage to release more cytokines, including more IL-1. IL-1 can also act on other cell types, but binding to the signaling cell itself helps regulate signal production. Autocrine signaling is also important in cancer cells. Many cancer cells release self-sustaining growth signals that act as autocrine mediators and help control cell division rates. In many breast cancer cases, cancer cells express progesterone receptors on their surface. Those receptors bind progesterone released by the cancer cells themselves, which can stimulate cell proliferation.

Self-Signaling Cells in Immunity and Cancer

self-signaling-cells-in-immunity-and-cancer

what is cell signaling?

How Cells Send and Receive Signals

Cell signaling lets cells send and receive messages from the environment and from other cells. Even with a protective membrane, cells need to detect changes and respond to them. Unicellular and multicellular organisms use signaling to stay coordinated and to react to outside cues. Cells often rely on receptor proteins in the membrane to sense information. Skin cells can respond to touch, and photoreceptors in the retina can detect light. Most cells respond to chemical signals such as hormones,...

internal receptors

Steroid Hormones and Intracellular Receptors

Steroid hormones and other small signaling molecules can pass through the cell membrane and bind to intracellular receptors inside the cell. These receptors are also called internal receptors. Many hydrophilic signals cannot cross the plasma membrane, so this pathway is used by signals that are small or hydrophobic. Nitric oxide, or NO, also uses this type of signaling. When a ligand, which is a signaling molecule, binds to a receptor in the cytoplasm or nucleus, the receptor changes shape.

contact-dependent cell communication

Cell-to-Cell Signaling via Channels

Cell-to-cell signaling can happen when neighboring cells are in direct contact. In this kind of communication, cells use receptor-ligand interactions or special cytoplasmic channels to move small molecules between them. In animal cells, these channels are called gap junctions. They form when six proteins called connexins assemble into a cylindrical structure in the plasma membrane called a connexon. When connexons from two adjacent cells line up, a channel opens between the cells. Enzymes help...

Autocrine signaling is a cell communication method in which a cell sends a signal to itself. The same cell releases an extracellular signaling molecule and also has receptors that can bind to that molecule. This lets the cell respond to its own message. In the immune system, this process is important for homeostasis, or keeping body conditions stable. A well-studied example is the macrophage, an immune cell that secretes cytokines such as interleukin-1, or IL-1. Macrophages also have membrane...

paracrine signaling

Local Cell Signaling in Blood and Healing

Local cell signaling helps cells communicate with nearby neighbors using released signaling molecules. These molecules act only over a short distance because they break down quickly or are inactivated if they are not taken up. This type of signaling supports processes such as nitric oxide signaling in blood vessels, neuron-to-neuron communication at synapses, blood clotting, tissue repair, and local allergic skin reactions. A clear example is nitric oxide signaling in blood vessels. The...

synaptic signaling

Chemical and Electrical Synapses

Neurons send signals across synapses, which are junctions between cells. These signals can excite or inhibit other neurons or target cells such as muscles. Most synapses are chemical. Some are electrical. Chemical synapses use action potentials, which are electrical impulses, to trigger the release of neurotransmitters. The sending neuron is the presynaptic neuron, and the receiving neuron is the postsynaptic neuron. An action potential travels along the axon and reaches the axon terminal,...

endocrine signaling

Hormones Travel to Distant Target Cells

Endocrine signaling uses hormones to send messages to target cells in other organs. Endocrine cells release these hormones into the circulatory system, which carries the signal through the body. Because the hormone reaches the whole organism, only cells with the right receptors respond. This kind of signaling usually acts slowly, but its effects last longer. Endocrine cells can use cell surface receptors or intracellular receptors, depending on the hormone. Cell surface receptors are...

bacterial signaling

Quorum Sensing in Bacteria

Quorum sensing lets bacteria coordinate behavior by sensing how many cells are nearby. Bacteria can signal inside the cell or between cells. When many bacteria act together, they can behave like a community and change gene expression as a group. This signaling starts with autoinducers, or AIs. Individual bacteria make AIs and release them across the cell membrane into the surrounding space. Some AIs diffuse out passively along a concentration gradient, while others are moved out by active...

yeast signaling

Yeast Cell Communication in Mating

Yeast cell communication helps control mating, colony growth, and other cell responses. Yeasts are single-celled organisms, but unlike bacteria, they are eukaryotes with a nucleus. Their signaling works much like cell signaling in other eukaryotic cells. A signal often begins when a ligand, such as a protein or small molecule released from a yeast cell, binds to a receptor on the cell surface. This binding activates second-messenger kinases, which then switch transcription factors on or off.

g protein-coupled receptors

GPCR Signaling Through G Proteins

G-protein coupled receptors, or GPCRs, start cell signaling after a ligand binds to the receptor. The receptor is a single polypeptide that crosses the cell membrane seven times. These membrane loops create an outside pocket that fits a specific ligand, such as a neurotransmitter or hormone. The inside loops connect to a G-protein.

enzyme-linked receptors

Trk Receptors in Cell Signaling

Trk receptors are enzyme-linked receptors that help cells respond to growth factors and some hormones. They belong to the receptor tyrosine kinase, or RTK, family. These receptors can trigger several signals inside a cell after they are activated. Neurotrophin receptors are one RTK group and include TrkA, TrkB, and TrkC, which are tropomyosin-related kinase receptors. TrkA binds nerve growth factor, neurotrophin-6, and neurotrophin-7. TrkB binds brain-derived neurotrophic factor, or BDNF, and...

ion channels

Ion Channels in Cells and Membranes

Ion channels are membrane proteins that help cells move ions across the plasma membrane. Ions such as sodium, potassium, and calcium move into and out of cells to maintain the electrochemical gradient. This gradient supports cell size and volume, nerve signaling, and gas and nutrient exchange. Ion channels are specialized integral membrane proteins that let specific ions pass down their electrochemical gradient. Their main job is to help keep the membrane potential, which is needed for cell...

what are second messengers?

Cell Signals That Use Second Messengers

Cell signals often use second messengers to carry messages inside the cell. Many receptor-binding ligands are hydrophilic, so they do not cross the cell membrane. Instead, the signal is relayed to an internal messenger that can spread the message farther. G-protein coupled receptors can activate the phosphoinositol pathway and the cyclic AMP, or cAMP, pathway. In the phosphoinositol pathway, the receptor activates phospholipase C. This enzyme hydrolyzes phosphatidylinositol biphosphate, or...

intracellular signaling cascades

Cell-Surface Receptor Signal Cascades

Cell-surface receptor signal cascades move information from outside the cell into the cytoplasm. This process is called signal transduction. It happens only with cell-surface receptors, because they cannot interact with most cell parts, such as DNA. Internal receptors are different. They can interact directly with DNA in the nucleus and help start protein synthesis. When a ligand binds to a receptor, the receptor changes shape. That shape change affects the receptor’s intracellular domain or...

key terms and concepts

Learn how autocrine signaling lets cells respond to their own signals. See macrophage IL-1 signaling and how cancer cells use self-made growth signals.

Self-Signaling Cells in Immunity and Cancer | JoVE K12

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Self-Signaling Cells in Immunity and Cancer

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