Name: cell adhesion in tissues and infection
Uploaded: 2023-04-30T11:55:15.000Z
Duration: 1 min 24 s
Channel: JoVE

부착 접합(adherens junction)은 상피와 같은 조직에서 세포를 함께 고정하는 고정 접합부(anchoring junction)입니다.
Adherens junction은 접착성 cadherins, anchoring actin cytoskeleton 및 linker catenins의 세 가지 주요 단백질 클래스를 포함하는 대규모 다중 단백질 복합체입니다.
Adherens 접합 조립은 세포막 근처에서 actin 단량체의 중합으로 시작하여 lamellipodia라고 하는 돌출부를 형성합니다.
이웃 세포의 얇은 판착지가 충분히 가까우면 표면의 cadherin이 상호 작용하여 더 많은 cadherin의 국소화를 유발하여 클러스터를 형성합니다.
이러한 클러스터는 베타, 알파 및 p120 카테닌에 의해 안정화되어 성장 부위에 더 많은 카데린-카테닌 복합체를 모집하는 데 도움이 됩니다.
두 세포 사이의 접촉 영역이 확장됨에 따라 알파-카테닌은 액틴 중합을 분지에서 분지화로 전환하고 세포막과 평행하게 배열합니다.
그런 다음 이러한 액틴 필라멘트는 미오신 (myosin)과 결합하여 수축 다발을 형성하여 성숙한 부착 접합을 형성합니다.
접합부는 한 세포의 세포골격을 다른 세포와 연결하며, cadherin 분자의 세포 외 상호 작용을 통해 함께 유지됩니다.

<ol>
	<li>Niessen, Carien M. 및 Cara J. Gottardi. "부착 접합의 분자 구성 요소." Biochimica et Biophysica Acta (BBA)-Biomembranes 1778.3 (2008) : 562-571.</li>
	<li>바움, 버즈, 마리오스 게오르기우. "상피 형성, 유지 관리 및 리모델링에서 부착 접합부의 역학." 세포 생물학 저널 192.6 (2011): 907-917.</li>
	<li>Mengaud, Jérôme, et al. "E-cadherin은 L. monocytogenes가 상피 세포에 진입하는 데 필요한 표면 단백질인 internalin의 수용체입니다."Cell 84.6 (1996): 923-932.</li>
</ol>

부착연접

Adherens Junctions

인접한 세포 사이의 강한 접촉점은 서로를 고정시켜 조직을 형성합니다. 이러한 부착연접에는 부착연접과 부착반점이라는 두 가지 유형이 있습니다. 부착 접합부는 상피 및 내피와 같은 조직에 풍부하여 부착 벨트라고 불리는 연속적인 부착 영역을 형성합니다. 심장 근육과 같은 다른 조직에서는 클러스터로 나타나 세포를 연결하여 조화로운 심장 근육 수축을 생성합니다.

부착연접은 동적입니다.

혈관을 둘러싸고 있는 내피 세포는 단단히 연결되어 있어 다른 세포와 분자가 혈류에서 주변 조직으로 빠져나가는 것을 막는 장벽을 형성합니다. 그러나 면역 반응 중에 혈류의 백혈구는 이 장벽을 통과하여 표적 조직에 도달해야 합니다. 히스타민과 같은 염증 분자와 혈관 내피 성장 인자(VGEF)와 같은 신호 전달 단백질은 내피 세포 표면에 존재하는 카드헤린의 인산화 및 내재화와 같은 하류 과정을 유발합니다. 이는 부착 접합부의 분해로 이어지고 면역 세포 및 기타 분자가 통과할 수 있는 틈을 만들어 내피 투과성을 증가시킵니다. 따라서 부착 접합의 유지 및 파괴는 특정 자극에 반응하여 동적으로 조절됩니다.

부착연접 및 감염

대장균과 같은 감염성 병원체는 부착연접을 파괴하고 세포간 틈을 통해 이동하여 숙주 조직에 들어갈 수 있습니다. 이 박테리아는 카드헤린의 세포외 도메인을 절단하는 프로테아제를 생산하여 접합 분해를 유발합니다. 세포 표면의 카드헤린은 또한 폐렴구균과 같은 박테리아에 의해 수용체로 탈취되어 상부 호흡기 상피에 부착됩니다.

그러나 가장 인상적인 하이재킹은 아마도 리스테리아 모노사이토제네스에 의해 입증되었을 것입니다. 이 박테리아는 E-카드헤린을 부착하고 해당 부위에 ɑ, β 및 p120-카테닌의 모집을 유발하는 세포벽 단백질을 발현합니다. 이러한 모집은 동적 액틴 중합을 시작하여 유도된 식세포작용이라고 불리는 과정에서 박테리아를 삼키는 막 돌출부를 형성합니다. 따라서 박테리아는 비식세포로 진입하여 숙주 내에서 증식합니다.

인접한 세포 사이의 강력한 접촉점은 세포를 서로 고정시켜 조직을 형성합니다. 이러한 앵커링 접합부는 두 가지 유형이 있습니다 – 접착 ...

Education

교육

JoVE Core

Cell Biology

세포생물학

Unit 1

제1단원

Cell-Cell Interactions

세포 간 상호작용

KEY TERMS AND CONCEPTS

주요 용어 및 개념

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 endothelial cells form a barrier that normally keeps cells and molecules inside the bloodstream. During an immune response, leukocytes, or white blood cells, must cross this barrier to reach damaged tissue. Inflammatory molecules such as histamines and signaling proteins such as vascular endothelial growth factor, or VEGF, can trigger phosphorylation and internalization of cadherins on the endothelial cell surface. Cadherins are adhesion proteins that help cells stick together. When this happens, adherens junctions break down, permeability increases, and gaps open for immune cells and other molecules to pass through.

Some infections also take advantage of adherens junctions. Helicobacter pylori can disrupt these junctions by producing proteases that cut the extracellular part of cadherins. This breaks the junctions and helps the bacteria move through the spaces between cells. Other bacteria, such as Streptococcus pneumoniae, use cadherins as receptors to attach to the upper respiratory epithelium. Listeria monocytogenes uses a more complex strategy. It binds E-cadherins and recruits alpha-, beta-, and p120-catenins, which starts actin polymerization. This creates membrane protrusions that engulf the bacteria in induced phagocytosis, allowing it to enter a nonphagocytic cell and multiply inside the host.

Cell Adhesion in Tissues and Infection

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 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...

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

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 adherens junctions hold tissues together, open during immune responses, and can be disrupted by bacteria like H. pylori, S. pneumoniae, and Listeria.

Cell Adhesion in Tissues and Infection | 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 Adhesion in Tissues and Infection

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