Name: steroid hormone signaling with intracellular receptors
Uploaded: 2023-04-30T11:39:14.000Z
Duration: 1 min 7 s
Channel: JoVE

Internal receptors are soluble proteins that bind signaling molecules inside cells, either in the cytoplasm or nucleus, to trigger responses, such as changes in gene expression.
Typically, the ligands that bind to internal receptors are hydrophobic, non-polar molecules that diffuse through the plasma membrane of the targeted cells or are compounds that may be synthesized intracellularly.
For example, the hormone testosterone or its enzymatically processed form dihydrotestosterone, or DHT, binds to an androgen receptor in the cytoplasm.
The receptor-ligand complexes move into the nucleus and dimerize. The DNA-binding site of the receptor recognizes and binds to specific nucleotide sequences called hormone or androgen-response elements.
The binding modulates the activity of specific genes, either promoting or blocking the synthesis of mRNAs that mediate androgen-specific effects in cells.

types of receptors: internal receptors

Types of Receptors: Internal Receptors

Many cellular signals are hydrophilic and cannot pass through the plasma membrane. However, small or hydrophobic signaling molecules can cross the hydrophobic core of the plasma membrane and bind intracellular receptors that reside within the cell cytoplasm or nucleus. Many mammalian steroid hormones and nitric oxide (NO) gas use this cell signaling mechanism.
Similar to membrane-bound receptors, the binding of a ligand to the intracellular receptor of causes a conformational change in the receptor to activate it. Like transcription factors, the active receptor can bind to receptor-specific DNA binding sites to increase or decrease the transcription of the 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. For 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 into 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, the binding of activated estrogen receptors to EREs may cause an increase or decrease in the transcription of target genes.
Activating other intracellular receptors, such as some thyroid hormone receptors, requires ligands to cross both the plasma membrane and nuclear membrane, as the corresponding receptors usually reside in the nucleus.

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

Education

JoVE Core

Cell Biology

Unit 1

Principles of Cell Signaling

KEY TERMS AND CONCEPTS

steroid hormone signaling with intracellular receptors

Steroid hormones and other small signaling molecules can enter the cell and bind intracellular receptors. These receptors are found in the cytoplasm or the nucleus. Because the ligands are hydrophobic, they can cross the plasma membrane, unlike many hydrophilic signals.

When a ligand binds an intracellular receptor, the receptor changes shape and becomes active. The active receptor can work like a transcription factor. It binds to specific DNA sites and can increase or decrease the transcription of target genes.

If the receptor is in the cytoplasm, the receptor-ligand complex must move into the nucleus before it can affect gene expression. Estrogen and testosterone are examples of steroid hormones that use this pathway. Estrogen can diffuse across the membrane, bind its receptor, and cause the receptors to dimerize, or pair up, before the complex enters the nucleus.

Inside the nucleus, the estrogen receptor complex binds DNA sequences called estrogen-response elements, or EREs. Other transcription factors and co-activators can change whether this binding raises or lowers gene transcription. Some thyroid hormone receptors also work as intracellular receptors, but their ligands must cross both the plasma membrane and the nuclear membrane because the receptors usually already reside in the nucleus. Nitric oxide, or NO gas, also uses this cell signaling mechanism.

Steroid Hormone Signaling with Intracellular Receptors

steroid-hormone-signaling-with-intracellular-receptors

overview of cell signaling

Cell Signaling Pathways and Responses

Cell signaling pathways help cells detect changes and respond to their environment. Cells also use signaling to communicate with other cells. Both unicellular and multicellular organisms rely on these signaling systems to share information. Cells often receive messages through receptor proteins on the cell membrane. Skin cells can respond to touch, and photoreceptors in the retina can detect light. Most cells respond to chemical signals such as hormones and neurotransmitters, and the same...

types of signaling molecules

Cell Signals That Travel Between Cells

Cell signals that travel between cells carry information in multicellular organisms. These signaling molecules can be small peptides, nucleotides, steroids, fatty acid derivatives, or dissolved gases such as nitric oxide. Some signals act near the cell that released them, while others move over long distances. Other signals stay on the cell surface and work only when cells make contact. Some signaling proteins need extra processing before they can act. Peptide and protein signals are made as...

types of receptors: cell surface receptors

types-of-receptors-cell-surface-receptors

Cell Surface Receptors and Signal Relay

Cell-surface receptors help cells detect signals outside the cell and relay them inward. They are also called transmembrane receptors because they sit in the cell membrane and span the plasma membrane. A ligand is the molecule that binds to the receptor, and it does not need to enter the cell to trigger a response. These receptors are membrane-anchored, integral proteins. They have three main parts. The extracellular domain binds the ligand outside the cell, the transmembrane domain passes...

Steroid hormones and other small signaling molecules can enter the cell and bind intracellular receptors. These receptors are found in the cytoplasm or the nucleus. Because the ligands are hydrophobic, they can cross the plasma membrane, unlike many hydrophilic signals. When a ligand binds an intracellular receptor, the receptor changes shape and becomes active. The active receptor can work like a transcription factor. It binds to specific DNA sites and can increase or decrease the...

assembly of signaling complexes

Protein Docking in Cell Signaling

Protein docking helps cells build signaling complexes that pass messages inside the cell. These multiprotein complexes form through protein-protein interactions at the cytoplasmic side of transmembrane receptors. They can also include enzymatic and non-enzymatic proteins linked to the receptor. Together, they help activate and spread intracellular signals that control cell functions. Cell signaling often depends on interaction domains, which are protein parts that recognize specific binding...

interactions between signaling pathways

Cross-Talk in Cell Signaling Pathways

Cell signaling pathways often cross-talk with one another. This means one pathway can influence another instead of acting alone. Cells use these linked pathways to combine signals from the environment and respond in a controlled way. One common pattern is convergence. In convergence, two separate signaling pathways meet at the same functional unit. That unit may be a single protein or a protein complex. The final response can be different from, or stronger than, the response from either...

amplifying signals via second messengers

Cell-Surface Receptors and Second Messengers

Cell-surface receptors use second messengers to carry signals into the cell. Many receptor-binding ligands are hydrophilic, so they do not cross the cell membrane. Instead, they bind to receptors on the outside of the cell and pass the message to the cytoplasm. G protein-coupled receptors can activate the phosphoinositol pathway and the cAMP pathway. In the phosphoinositol pathway, the receptor activates phospholipase C. This enzyme splits phosphatidylinositol biphosphate, or PIP2, into two...

amplifying signals via enzymatic cascade

Turning Off Amplified Cell Signals

Cell signaling depends on both signal amplification and signal shutoff. When a ligand binds to a cell-surface receptor, the receptor changes shape inside the cell. That change can activate an enzyme function or let the receptor bind other molecules. In many signal transduction pathways, one ligand can trigger many downstream targets, so the signal is amplified. Proteins that pass the signal are often phosphorylated, which means a phosphate group is added at one or more sites. This modification...

diversity in cell signaling responses

Cell Signaling Response Speed and Patterns

Cell signaling responses can differ in both pattern and speed. A cell’s function and communication depend on outside signals, internal signaling pathways, and the response that follows. Different cell types do not use the same set of signaling parts. Receptors are selective for their matching ligands, but once activated, they can affect DNA transcription, protein synthesis, and metabolism. Some signaling systems produce graded responses. In a graded response, the cell output changes in...

cell signaling feedback loops

How Cells Balance Signal Strength

Cell signaling is controlled by feedback loops that connect a cell’s output back to its input. Positive feedback and negative feedback help keep signaling systems working in the right range. These loops are especially important when cells need to respond quickly and then adjust that response. Negative feedback loops act as output limiters in many signaling systems. After an input signal starts a response, the response rises quickly until it reaches a threshold. Beyond that point, the negative...

cell signaling in plants

Plant Receptor Kinases and Growth Signals

Plant receptor kinases help cells communicate and control growth, flowering, fruiting, and activity in roots, shoots, and leaves. These signals also help plants respond to changing environmental conditions. Plant signaling works differently from animal signaling, so the receptors used in plants are not the same as those commonly found in animals. Plants mainly use enzyme-linked receptors. In animals, the largest class of cell-surface receptors is the G-protein coupled receptor, or GPCR.

plant hormones

Plant Hormones and Growth Signals

Plant hormones are chemical signals that help control growth and development in plants. They allow different parts of a plant to communicate and respond to changes in the environment. The main plant hormones include auxin, gibberellins, cytokinins, abscisic acid, and ethylene. Each one has a different role, but they often work together to shape how a plant grows, matures, and reacts to stress. Auxin helps direct plant growth, while gibberellins support stem elongation and seed germination.

key terms and concepts

Learn how steroid hormones, nitric oxide, and thyroid hormone signals enter cells, bind intracellular receptors, and change gene transcription in high school biology.

Steroid Hormone Signaling with Intracellular Receptors | JoVE K12

cell biology

JoVE Core Cell Biology illustrates complex cellular processes in easy-to-understand yet comprehensive animated video lessons. This collection focuses on the essential components and functions of cells, including organelles and membranes, cellular transport, and cell energetics. It is complemented by scientist-in-action videos that demonstrate the application of cell biology in real-world research experiments.

Steroid Hormone Signaling with Intracellular Receptors

Description

Transcript

Tags