Name: internal receptors and hormone signals
Uploaded: 2021-04-07T12:11:59.000Z
Duration: 1 min 56 s
Channel: JoVE

Internal receptors are soluble proteins found in either the cytoplasm or the nucleus. They bind signaling molecules called ligands inside the cell and trigger cellular responses, such as changes in gene expression.Typically, ligands that bind to internal receptors are hydrophobic, nonpolar molecules that can diffuse through the plasma membrane without needing a membrane receptor. Some signaling molecules can also be synthesized inside the target cell.Once a ligand binds, the receptor changes shape and interacts with other regulatory elements in the cell.For example, the hormone testosterone, or its converted form dihydrotestosterone, also called DHT, binds to androgen receptors located in the cytoplasm.After binding, the receptor-ligand complex changes structure and exposes its DNA-binding region. This change also allows the receptors to form dimers and move into the nucleus.Inside the nucleus, the activated receptor binds to specific DNA sequences called hormone-response elements. In androgen signaling, these sequences are called androgen-response elements.By binding to these DNA sequences, the receptor recruits other cellular machinery that helps regulate gene activity by increasing or decreasing the expression of specific target genes.These changes in gene expression lead to androgen-related effects in target tissues, such as muscles, the prostate, and hair follicles.

internal receptors

Internal Receptors

Many cellular signals are hydrophilic and therefore cannot pass through the plasma membrane. However, small or hydrophobic signaling molecules can cross the hydrophobic core of the plasma membrane and bind to internal, or intracellular, receptors that reside within the cell. Many mammalian steroid hormones use this mechanism of cell signaling, as does nitric oxide (NO) gas.

Similar to membrane-bound receptors, binding of a ligand to a receptor located in the cytoplasm or nucleus of a cell causes a conformational change in the receptor. Like transcription factors, the active receptor can bind to receptor-specific DNA binding sites to increase or decrease the transcription of target genes. In the case of an intracellular receptor located in the cytoplasm, the receptor-ligand complex must first cross the nuclear membrane.

Many steroid hormones, including estrogen and testosterone, use intracellular receptors to induce specific effects. As an example, estrogen can diffuse across the membrane; binding of estrogen to its receptor results in dimerization of the receptors and transport of the ligand-receptor complex to the nucleus. Once in the nucleus, the complex can bind to DNA sequences called Estrogen-Response Elements (EREs). Depending on the other transcription factors and co-activators, binding of activated estrogen receptors (ERs) to EREs may cause an increase or decrease in transcription of target genes.

The activation of other intracellular receptors, including some thyroid hormone receptors, requires that ligands cross both the plasma membrane and nuclear membrane, as the corresponding receptors reside in the nucleus. These ligand-receptor complexes then can bind to DNA, similar to the mechanism described above.

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

https://cloudfront.jove.com/files/ftp_upload/11011/11011_article_thumb_11011.jpg

Education

JoVE Core

Molecular Biology

Unit 2

Cell Signaling Pathways

KEY TERMS AND CONCEPTS

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.

This topic connects hormone signaling to cell function in a simple way. It shows how some signals travel through the body and then act inside target cells. Understanding internal receptors helps explain how cells respond to hormones in a precise and controlled way.

Internal Receptors and Hormone Signals

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 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

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...

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

Learn how internal receptors bind hormones inside cells and help trigger responses after signals pass through the cell membrane in high school biology.

Internal Receptors and Hormone Signals | 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.

Internal Receptors and Hormone Signals

Description

Transcript

Tags