Name: local cell communication in tissues
Uploaded: 2021-04-07T12:11:59.000Z
Duration: 1 min 32 s
Channel: JoVE

Cells use paracrine signaling to communicate with nearby cells.In paracrine signaling, a cell releases signaling molecules that diffuse over short distances.As a result, these molecules trigger responses only in neighboring cells that possess the appropriate cell-surface receptors or intracellular target proteins.Signaling molecules that do not bind to receptors are rapidly degraded or inactivated, limiting the range of the signal.For example, physical activity, such as exercise, increases oxygen demand in skeletal muscles. To meet this increased demand, endothelial cells lining nearby blood vessels release nitric oxide gas, or NO, which acts as a paracrine mediator.NO diffuses through the extracellular matrix into neighboring smooth muscle cells, where it interacts with intracellular target proteins and triggers signaling pathways that cause the cells to relax.As a result, the blood vessels dilate, increasing blood flow to the active tissues.Like many other paracrine signaling molecules, NO is very short-lived outside endothelial cells and produces only a localized response.

paracrine signaling

Paracrine Signaling

Paracrine signaling allows cells to communicate with their immediate neighbors via secretion of signaling molecules. Such a signal can only trigger a response in nearby target cells because the signal molecules degrade quickly or are inactivated if not taken up. Prominent examples of paracrine signaling include nitric oxide signaling in blood vessels, synaptic signaling of neurons, the blood clotting system, tissue repair/wound healing, and local allergic skin reactions.Nitric oxide as a Paracrine Signaling MoleculeBlood vessels contain several layers of cells. The innermost layer of cells called the endothelium have nitric oxide synthase, which produces nitric oxide as a paracrine mediator. The nitric oxide that reaches the blood does not contribute to signaling but immediately reacts with biochemicals, such as hemoglobin. However, nitric oxide molecules that diffuse towards the smooth muscle cells surrounding the blood vessel facilitate their relaxation and vasodilation, and ultimately a decrease in blood pressure. At the molecular level, this signaling mechanism involves the binding of the nitric oxide molecules to guanylate cyclase receptors, which increases the levels of cyclic guanosine monophosphate (cGMP) in the smooth muscle cells.Paracrine Signaling and Blood ClottingAnother example of paracrine signaling is blood clotting. When a blood vessel is damaged and begins to bleed, the endothelium has been broken. Broken endothelial tissue releases von Willebrand factors (vWF), which bind to platelet cells circulating in the blood via paracrine signaling. Meanwhile, collagen fibers under the endothelial cells also bind to the platelets. Several other platelet proteins are subsequently activated and released by the platelets. These proteins then activate more platelets via paracrine signaling. A complex series of reactions between many clotting factors forms a substance known as fibrin, which holds the blood clot together and patches the broken endothelium.

Paracrine signaling allows cells to communicate with their immediate neighbors via secretion of signaling molecules. Such a signal can only trigger a ...

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Education

JoVE Core

Molecular Biology

Unit 2

Cell Signaling Pathways

KEY TERMS AND CONCEPTS

local cell communication in tissues

Paracrine signaling is a form of local cell communication in tissues. In this process, one cell releases chemical signals that affect nearby target cells. Because the signal stays close to where it is made, paracrine signaling helps cells coordinate responses within a limited area.

These signals do not travel far through the body. Instead, they move through the space around neighboring cells and bind to specific receptors on target cells. This nearby action makes paracrine signaling different from long-distance communication between cells.

Paracrine signaling is important in many tissue responses. It allows cells to send messages quickly to nearby cells without using the bloodstream as a route. For high school biology, it is a key example of how cells communicate in a controlled and localized way.

Local Cell Communication in Tissues

notch signaling pathway

Notch Cell Communication and Gene Control

Notch signaling is a conserved cell-to-cell communication pathway in animals. It is unusual because the Notch protein acts as both the receptor and the main signaling molecule. The pathway was first linked to a mutant wing shape in Drosophila melanogaster, where changes in the Notch gene caused a serrated, or "notched," wing margin. The Notch gene was later shown, in 1985, to encode a transmembrane surface receptor. Signaling starts when the Notch receptor on one cell directly binds the Delta...

canonical wnt signaling pathway

Wnt Signals in Development and Disease

Wnt signaling helps cells communicate during development and in adult tissues. The Wnt proteins were first discovered nearly four decades ago in genetic studies of body pattern defects in Drosophila. One gene was named wingless, or wg, because of the fly phenotype it caused. Around the same time, Harold Varmus found that a murine tumor virus activated the mammalian wg homolog, Int-1, and this activity led to tumor formation in mice. The gene family was later called Wnt, a name built from...

hedgehog signaling pathway

Hedgehog Signaling in Growth and Disease

Hedgehog signaling helps guide organ development and tissue balance in both invertebrates and vertebrates. The Hedgehog gene was first identified because it affected the growth of disorganized, hair-like bristles in Drosophila, which looked like hedgehog spines. In mammals, the pathway includes Sonic Hedgehog (Shh), Desert Hedgehog (Dhh), and Indian Hedgehog (Ihh), which each carry out specialized roles in development. Mammalian Hedgehog signaling also depends on the primary cilium, a...

nf-&#954;b-dependent signaling pathway

NF-κB in Immune Defense and Disease

NF-κB is a transcription factor that helps control immune defense and inflammation in animals. It was discovered in 1986 in the lab of Nobel laureate Professor David Baltimore because of its interaction with the immunoglobulin light chain enhancer in B-cells. Since then, researchers have shown that NF-κB regulates the expression of more than 100 genes. Many of the genes controlled by NF-κB support innate and adaptive immune responses. They also help drive inflammatory responses. In this way,...

internal receptors

Internal Receptors and Hormone Signals

Internal receptors are proteins inside a cell that bind signaling molecules. These receptors help certain hormones send messages after they pass through the cell membrane. Because the receptor is internal, the signal acts from within the cell rather than at the surface. Many internal receptors respond to steroid hormones. These hormones can cross the membrane and reach the receptor inside the cell. Once the hormone binds, the receptor can help trigger a response that changes cell activity. <br...

circadian rhythms and gene regulation

Light Control of the Biological Clock

Light helps control the biological clock by shaping circadian rhythms. These 24-hour cycles affect how cells, body systems, and behavior stay in sync with day and night. In animals, this timing system helps regulate complex physiology. The study of circadian rhythm began in 1935, when German zoologists Hans Kalmus and Erwin Bünning found it in Drosophila melanogaster, the fruit fly. The molecular basis stayed unclear for decades. In 1984, Jeffrey C. Hall, Michael Rosbash, and Michael W. Young...

what is cell signaling?

Cell Signaling in Cell Communication

Cell signaling is a key part of cell communication. It helps cells send, receive, and respond to signals so they can work together. A signal starts when a cell releases a molecule. Another cell detects that molecule with a receptor, which is a protein that binds the signal. This binding begins a signaling pathway inside the cell. The pathway carries the message through the cell in a process called signal transduction. In the end, the cell produces a response. That response can change cell...

autocrine signaling

Autocrine Cell Communication

Autocrine cell communication is a signaling process in which a cell sends a message to itself. In this pathway, the cell releases a signaling molecule and also has receptors that can detect that same molecule. This makes the cell both the sender and the receiver. Autocrine signaling is common in cell communication and is often grouped with cytokine signaling. Cytokines are small signaling proteins that help cells communicate, especially in immune responses and growth control. In autocrine...

Paracrine signaling is a form of local cell communication in tissues. In this process, one cell releases chemical signals that affect nearby target cells. Because the signal stays close to where it is made, paracrine signaling helps cells coordinate responses within a limited area. These signals do not travel far through the body. Instead, they move through the space around neighboring cells and bind to specific receptors on target cells. This nearby action makes paracrine signaling different...

endocrine signaling

Hormones in Endocrine Signaling

Endocrine signaling uses hormones to send messages through the body. These signals travel through the bloodstream from one cell or gland to another target cell. The target cell responds only if it has the right receptor to detect the hormone. This type of cell communication helps coordinate many body functions at a distance. Because the signal moves through the blood, the source and the target do not need to be close together. Endocrine signaling is a key way cells regulate activity in other...

what are second messengers?

Cell Signals and Second Messengers

Second messengers are small molecules that help cells pass along signals after a receptor is activated. They carry the message inside the cell and help start a response to the outside signal. This signaling step is important in cell communication. It helps the signal move from the cell membrane to targets deeper inside the cell. Second messengers make that relay possible and help the cell respond in a controlled way. Common second messengers include cyclic AMP, calcium ions, and inositol...

intracellular signaling cascades

Cell Signaling Cascades Inside Cells

Cell signaling cascades inside cells relay messages from one molecule to the next. These pathways help a cell respond to a signal in a controlled way. The signal is often carried through a series of steps, which can amplify the original message. A signaling cascade may involve a receptor at the cell surface and molecules inside the cell that pass the message along. Each step can trigger the next step in the chain. This makes the response specific and allows the cell to act on the signal at the...

g-protein coupled receptors

G-protein Receptors in Cell Signaling

G-protein coupled receptors help cells receive and pass along signals. These membrane receptors sit in the cell membrane and respond when a ligand binds to them. A ligand is a molecule that fits and attaches to a receptor. When a ligand binds, the receptor changes shape. That shape change activates a G protein inside the cell. The G protein then helps start the signal inside the cell. These receptors are important because they connect outside signals to inside responses. They are a major part...

enzyme-linked receptors

How Enzyme-Linked Receptors Signal

Enzyme-linked receptors help cells respond to signals outside the cell. They are a major class of cell-surface receptors, and they work by triggering enzyme activity after a signal binds. Many enzyme-linked receptors are receptor tyrosine kinases. When a signaling molecule binds, the receptor changes shape and activates its enzyme side. This starts a signaling step inside the cell that can affect cell behavior. These receptors are important in cell communication. They help carry messages from...

non-canonical wnt signaling pathways

Wnt Pathways That Guide Cell Position

Wnt signaling helps guide early embryonic development and later life processes in animals. It is controlled by Wnt proteins, which can trigger different intracellular pathways depending on which receptors and co-receptors they bind. These signals support organ formation in the embryo and help maintain neuronal and blood stem cells. The non-canonical Wnt pathways are the β-catenin independent routes. They are more diverse and less well characterized than the canonical Wnt/β-catenin pathway. Two...

key terms and concepts

Explore paracrine signaling as local cell communication, where signals act on nearby target cells and help tissues coordinate responses.

Local Cell Communication in Tissues | JoVE K12

molecular biology

JoVE Core Molecular Biology showcases the molecular processes of the cell through clear and concise animated video lessons. Additionally, in scientist-in-action videos, these concepts' application is demonstrated through real experiments in modern laboratories.

Local Cell Communication in Tissues

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