Name: cell surface receptors and signal relay
Uploaded: 2023-04-30T11:39:06.000Z
Duration: 1 min 28 s
Channel: JoVE

Transmembrane receptors are proteins on the cell surface that function as signal transducers and initiate intracellular signaling cascades.
They may be classified as ion channel receptors, G-protein coupled receptors, and enzyme-linked receptors.
Ion channel receptors are divided into two subtypes. The ligand-gated channels open when a ligand binds to the receptor allowing ions to diffuse through the channel.
In contrast, the voltage-gated channels open and close in response to changes in the charge difference across the membrane, allowing ions to move into or out of the cell.&#160;&#160;
G-protein coupled receptors or GPCRs have their cytoplasmic domain coupled to a heterotrimeric GTP-binding protein. Ligand binding stimulates the exchange of the GDP in the alpha subunit of G-protein with a GTP. This causes the alpha and beta-gamma subunits to dissociate and interact with other effector proteins.
Enzyme-linked receptors either have a cytoplasmic domain that can function as an enzyme or associate directly with intracellular enzymes. Ligand binding promotes receptor dimerization and enzyme activation.

types of receptors: cell surface receptors

Types of Receptors: Cell Surface Receptors

Cell-surface receptors, also known as transmembrane receptors, are cell surface, membrane-anchored (integral) proteins that bind to external ligand molecules. This type of receptor spans the plasma membrane and performs signal transduction, converting an extracellular signal into an intracellular signal. Ligands that interact with cell-surface receptors do not have to enter the cell that they affect. Cell-surface receptors are also called cell-specific proteins or markers because they are specific to individual cell types.
Each cell-surface receptor has three main components: an external ligand-binding domain called the extracellular domain, a hydrophobic membrane-spanning region called a transmembrane domain, and an intracellular domain inside the cell. The size and extent of each of these domains vary widely, depending on the type of receptor. Cell-surface receptors are involved in most of the signaling in multicellular organisms. There are three general categories of cell-surface receptors: ion channel-linked receptors, G-protein-linked receptors, and enzyme-linked receptors.
Because cell-surface receptor proteins are fundamental to normal cell functioning, it should be no surprise that a malfunction in any of these proteins could have severe consequences. Errors in the protein structures of certain receptor molecules have been shown to play a role in hypertension (high blood pressure), asthma, heart disease, and cancer.
This text is adapted from <a href="https://openstax.org/books/biology-2e/pages/9-1-signaling-molecules-and-cellular-receptors">Openstax, Biology 2e, Chapter 9 Cell communication, Section 9.1: Signaling molecules and cellular receptors</a>.

Cell-surface receptors, also known as transmembrane receptors, are cell surface, membrane-anchored (integral) proteins that bind to external ligand ...

types-of-receptors-cell-surface-receptors

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JoVE Core

Cell Biology

Unit 1

Principles of Cell Signaling

KEY TERMS AND CONCEPTS

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 through the membrane, and the intracellular domain stays inside the cell. The size of each region can vary widely depending on the receptor.

Cell-surface receptors are also called cell-specific proteins or markers because they are specific to individual cell types. They play a major role in signaling in multicellular organisms. The three general categories are ion channel-linked receptors, G-protein-linked receptors, and enzyme-linked receptors.

These proteins are essential for normal cell function, so a problem in receptor structure can have serious effects. Changes in certain receptor molecules have been linked to hypertension, asthma, heart disease, and cancer. Because of this, cell-surface receptors are an important part of cell communication and human health.

Cell Surface Receptors and Signal Relay

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...

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...

types of receptors: internal receptors

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...

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 cell-surface receptors span the membrane, bind ligands outside the cell, and relay signals inside through major receptor types.

Cell Surface Receptors and Signal Relay | 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.

Cell Surface Receptors and Signal Relay

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