Name: selectins in immune cell capture
Uploaded: 2023-04-30T11:56:02.000Z
Duration: 1 min 25 s
Channel: JoVE

셀렉틴(Selectin)은 탄수화물 리간드와 결합하여 일시적인 세포-세포 접착에 참여하는 세포 표면 당단백질입니다.
모든 셀렉틴은 N-말단 렉틴 도메인(N-terminal lectin domain)과 표피 성장 인자(epidermal growth factor) 또는 EGF 도메인(EGF domain)으로 구성되며, 이들은 결합 특이성과 강도를 조절합니다.
그러나, sequence-conserved-repeats 또는 SCR domain의 수는 selectin의 유형에 따라 2회에서 9회까지 다양할 수 있습니다.
림프구와 같은 면역 세포에서 발현되는 짧은 L-셀렉틴은 내피 세포의 리간드를 결합하여 림프절로 이동하는 데 도움을 줍니다.
더 큰 P-셀렉틴은 주로 혈소판에서 발현됩니다. 그들은 부상 부위에서 혈소판과 면역 세포를 응집하는 데 도움이 됩니다.
E-셀렉틴(E-selectins)이라고 하는 세 번째 유형은 면역 반응 중에 내피 세포에서 P-셀렉틴과 함께 시간적으로 발현됩니다.
이러한 셀렉틴은 자유롭게 흐르는 백혈구와 약하고 일시적인 상호 작용을 형성하고 속도를 늦춥니다.
그런 다음 백혈구는 내피 표면을 따라 굴러가며, 여기서 다른 세포 접착 분자는 백혈구 귀환이라고 하는 과정을 통해 적절한 조직 미세환경으로 모집하는 데 도움을 줍니다.

<ol>
	<li>Borsig, Lubor. "암 면역의 셀렉틴." 당생물학 28.9 (2018): 648-655.</li>
	<li>Gout, Stéphanie, Pierre-Luc Tremblay 및 Jacques Huot. "암세포 유출 및 전이의 장기 선택성에서 셀렉틴 및 셀렉틴 리간드." 임상 및 실험 전이 25.4 (2008): 335-344.</li>
</ol>

셀렉틴

Selectins

세포 접착은 다세포성의 필수적인 측면입니다. 안정적인 세포 상호작용은 일반적으로 동일한 유형의 세포 사이에서 발생하지만, 일시적인 세포 상호작용은 호중구와 내피 세포 등 서로 다른 조직 유형의 세포 사이에서 발생합니다. 셀렉틴은 탄수화물 리간드와 결합하여 일시적인 세포 접착을 형성하는 세포 접착 분자(CAM)의 한 종류입니다. 이는 칼슘 이온이 있는 경우에만 탄수화물과 결합하는 C형 렉틴인 렉틴 도메인으로 끝나는 다양한 길이의 긴 세포외 부분을 가진 막대 모양의 단백질입니다. 셀렉틴의 세 가지 주요 유형은 조직 특이성과 길이에 따라 식별됩니다(L-셀렉틴, P-셀렉틴 및 E-셀렉틴).

면역 반응의 셀렉틴

혈관을 둘러싸고 있는 내피 세포는 P-셀렉틴을 발현하고 이를 Weible-Palade 소체라고 불리는 소포체에 저장합니다. 염증 동안 히스타민 자극은 이러한 소포를 세포 표면으로 빠르게 동원합니다. 이러한 활성화된 내피 세포는 또한 E-셀렉틴 및 P-셀렉틴 유전자를 상향 조절하여 혈류에서 자유롭게 흐르는 백혈구를 모집하도록 준비합니다.

호중구 및 호산구와 같은 백혈구는 세포 표면에 PSGL-1과 같은 탄수화물 리간드를 발현합니다. 내피 세포에서 튀어나온 긴 셀렉틴은 이러한 리간드와 쉽게 상호 작용할 수 있으며 혈류에서 자유롭게 흐르는 백혈구를 "잡을" 수 있습니다. 셀렉틴은 처음에는 닫힌 형태이므로 리간드에 약하게 결합합니다. 그러나 백혈구가 따라 흐르면서 이러한 상호 작용의 전단 응력으로 인해 셀렉틴이 열리게 됩니다. 개방형 형태의 셀렉틴은 리간드에 강하게 결합하여 백혈구 속도를 늦추는 데 도움이 됩니다.

암의 셀렉틴

전이성 암세포는 정상적인 셀렉틴 매개 모집 과정을 가로채 건강한 조직을 침범합니다. 이러한 전이성 세포는 세포 표면에 탄수화물 리간드를 발현하므로 내피 세포에 결합하는 것을 수용하게 됩니다. 결합 시 암세포는 혈관 밖으로 유출이라는 과정을 통해 혈관 밖으로 빠져나갈 수 있습니다. 암세포는 새로운 부위에 침투하여 2차 종양을 생성할 수 있습니다.

세포 부착은 다세포성의 필수적인 측면입니다. 안정적인 세포 상호 작용은 일반적으로 동일한 유형의 세포 간에 발생하지만 일시적인 ...

Education

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JoVE Core

Cell Biology

세포생물학

Unit 1

제1단원

Cell-Cell Interactions

세포 간 상호작용

KEY TERMS AND CONCEPTS

주요 용어 및 개념

selectins in immune cell capture

Selectins help cells make short, temporary contacts during immune responses. They are cell adhesion molecules that bind carbohydrate ligands on other cells. These rod-like proteins have a long outside region and end in a lectin domain, which binds carbohydrates only when calcium ions are present.

Three main selectins are known: L-selectin, P-selectin, and E-selectin. Their names reflect where they are found and how long they are. This tissue specificity helps explain why selectins act in certain cell interactions instead of making permanent attachments.

In blood vessels, endothelial cells line the vessel wall and use selectins to recruit leukocytes during inflammation. These cells store P-selectin in vesicular bodies called Weibel-Palade bodies. When histamine stimulates the cells, the vesicles move quickly to the cell surface. The activated endothelial cells also increase E-selectin and P-selectin gene expression, which prepares them to attract free-flowing leukocytes.

Leukocytes such as neutrophils and eosinophils carry carbohydrate ligands on their surface, including PSGL-1. Long selectins on endothelial cells can reach out and catch these moving cells from the bloodstream. Selectins start in a closed form, so they bind weakly at first. As the leukocyte keeps moving, shear stress from the interaction opens the selectin. In the open form, the selectin binds more strongly and slows the leukocyte down.

Cancer cells can also use this same pathway. Metastatic cancer cells display carbohydrate ligands on their surface and can bind endothelial cells. This lets them leave the blood vessel by extravasation and enter a new tissue. Once there, they can grow into secondary tumors.

Selectins in Immune Cell Capture

cell adhesion molecules - types and functions

cell-adhesion-molecules-types-and-functions

Cell Adhesion Molecules in Tissues

Cell adhesion molecules help cells stick together and work as part of a tissue. They give multicellular organisms physical strength and also help cells send signals across the plasma membrane. These proteins are important for coordinated activity in tissues and organ systems. CAMs are grouped into four main families: integrins, cadherins, selectins, and immunoglobulin-like CAMs, or IgCAMs. Each family supports cell interactions in a different way. Some CAMs help cells attach firmly, while...

structure of cadherins

Cadherins in Cell Junctions and Disease

Cadherins are cell adhesion proteins that help cells stick together and build tissues. Their name comes from their calcium-dependent binding. Early examples were named E-cadherin, P-cadherin, and N-cadherin after the epithelial, placental, and neuronal cells where they were first found. Classical cadherins share similar sequences and structures. Other cadherins, including those involved in cell signaling, are grouped as non-classical cadherins. This diversity comes from multiple cadherin genes...

cadherins in tissue organization

Cadherins Guide Cell Sorting in Tissues

Cadherins help cells sort into the right tissues during development. They are a large superfamily of cell adhesion molecules, with more than 180 variants. Different tissues express specific cadherin combinations, which helps cells recognize and stick to the right neighbors. Cadherins usually bind to the same or a closely related cadherin on another cell. This is called homophilic binding. Because of this matching behavior, cells of the same type tend to group together and form clusters that...

catenins

Catenins in Cell Junctions and Signaling

Catenins help cells stay connected and also support signaling inside the body. These proteins act as linker proteins in cell junction complexes because they have multiple binding domains and flexible structures. Most catenins contain a protein sequence called the armadillo repeat, so they are also known as armadillo proteins. Alpha-catenin is the main exception. Catenins bind to cell adhesion molecules such as cadherins. They then connect cadherins to cytoskeletal proteins, and the exact link...

selectins

Selectins help cells make short, temporary contacts during immune responses. They are cell adhesion molecules that bind carbohydrate ligands on other cells. These rod-like proteins have a long outside region and end in a lectin domain, which binds carbohydrates only when calcium ions are present. Three main selectins are known: L-selectin, P-selectin, and E-selectin. Their names reflect where they are found and how long they are. This tissue specificity helps explain why selectins act in...

immunoglobulin-like cell adhesion molecules

immunoglobulin-like-cell-adhesion-molecules

Ig-CAMs in Neural Growth and Disease

Ig-CAMs, or immunoglobulin-like cell adhesion molecules, are cell surface glycoproteins in the immunoglobulin superfamily. They contain immunoglobulin domains, and some also have fibronectin type III domains. Their Ig domains can be glycosylated to different degrees. These molecules can bind to the same kind of Ig-CAM or to other ligands, such as integrins. Most Ig-CAMs help cells stick together only for a short time. The nectin class is different because it helps form stable junctions,...

overview of cell-cell junctions

Cell Junctions in Tissues

Cell junctions help hold tissues together and let neighboring cells communicate. In multicellular organisms, the three-dimensional shape of tissues depends on interactions between cells and the extracellular matrix. Cell-cell junctions are specialized structures made of multi-protein complexes on one cell that connect with similar complexes on another cell. These junctions are grouped into three main types based on function: occluding, anchoring, and gap junctions. Tight junctions, also called...

adherens junctions

Cell Adhesion in Tissues and Infection

Adherens junctions are strong cell-to-cell anchors that help tissues stay connected. These anchoring junctions work with desmosomes, another type of junction that holds adjacent cells together. In many epithelial and endothelial tissues, adherens junctions form a continuous adhesion belt. In heart muscle, they often appear as clusters that help cells work together for coordinated contraction. Adherens junctions are also dynamic, especially in the cells that line blood vessels. These...

tension response at adherens junctions

How Adherens Junctions Sense Force

Adherens junctions help cells stay attached while they respond to mechanical force. These multi-protein complexes can adapt to tensile force and shear stress. When the force changes, mechanosensory proteins in the junction can change shape. This process is called mechanotransduction. Alpha-catenin is one of the main force-sensing proteins in adherens junctions. It is an allosteric protein, which means its shape affects how it works. Alpha-catenin has three VH, or vinculin homology, domains...

desmosomes

Desmosomes and Cell Anchoring

Desmosomes are cell junctions that anchor cells together. They are button-like structures that create an interlinked network of intermediate filaments across cells. This strong link helps tissues resist mechanical stress and maintain tissue integrity. Desmosomes are built from multiple proteins. Their core includes desmosomal cadherins, which are adhesion proteins that bind to cadherins on neighboring cells. The two desmosomal cadherins are desmogleins and desmocollins. These transmembrane...

tight junctions

Tight Junction Proteins and Cell Barriers

Tight junction proteins form seals between neighboring cells. These molecular barriers help stop fluids, ions, and other small solutes from leaking across body cavities and tissue compartments in multicellular organisms. They are an important part of cell barriers in places where controlled movement matters. The main tight junction proteins are claudin and occludin. Other proteins include tricellulin and JAM, which stands for junctional adhesion molecule. Most of these proteins are 4-pass...

gap junctions

Cell Communication Through Gap Junctions

Gap junctions let adjacent animal cells share small molecules, ions, and secondary messengers. These communication channels connect the cytoplasm of neighboring cells. They are built from many molecular channels, often from a few hundred to thousands in one junction. Each channel is made of two halves called connexon hemichannels. A connexon is a hexamer, meaning it is formed by six transmembrane connexin proteins. The six proteins arrange in a ring and create a pore in the center. One...

key terms and concepts

Learn how selectins help leukocytes slow down, how inflammation activates endothelial cells, and how metastatic cancer cells use the same pathway.

Selectins in Immune Cell Capture | 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.

Selectins in Immune Cell Capture

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