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

接着結合は、上皮などの組織内で細胞を一緒に保持する固定結合です。
Adherensジャンクションは、接着性カドヘリン、アンカリングアクチン細胞骨格、およびリンカーカテニンの3つの主要なタンパク質クラスを含む大規模なマルチタンパク質複合体です。
接着結合アセンブリは、細胞膜付近のアクチンモノマーの重合から始まり、ラメリポディアと呼ばれる突起を形成します。
隣接する細胞のラメリポディアが十分に接近すると、その表面のカドヘリンが相互作用して、より多くのカドヘリンの局在化を引き起こし、クラスターを形成します。
これらのクラスターは、ベータカテニン、アルファカテニン、およびp120カテニンによって安定化されており、成長部位により多くのカドヘリン-カテニン複合体を動員するのに役立ちます。
2つの細胞間の接触領域が拡大すると、α-カテニンはアクチン重合を分岐から非分岐に移行し、細胞膜に平行に配置します。
次に、これらのアクチンフィラメントはミオシンと結合して収縮束を形成し、成熟した接着結合を形成します。
この接合部は、ある細胞の細胞骨格を別の細胞と結びつけ、カドヘリン分子の細胞外相互作用を介してまとめられています。

<ol>
	<li>「接着接合部の分子成分」 Biochimica et Biophysica Acta (BBA)-Biomembranes 1778.3 (2008): 562-571.</li>
	<li>「上皮の確立、維持、およびリモデリングにおける付着者接合のダイナミクス」 Journal of Cell Biology 192.6 (2011): 907-917.</li>
	<li>「E-カドヘリンは、L. monocytogenesの上皮細胞への侵入に必要な表面タンパク質であるインターナルリンの受容体である」 Cell 84.6 (1996): 923-932.</li>
</ol>

接着接合部

Adherens Junctions

隣接する細胞間の強力な接触点により細胞同士が固定され、組織が形成されます。 このような固定結合には、アドヘレンスジャンクションとデスモソームという 2 つのタイプがあります。 接着接合部は上皮や内皮などの組織に多く存在し、接着ベルトと呼ばれる連続した接着領域を形成しています。 心筋などの他の組織では、それらはクラスターとして現れ、細胞を結び付けて協調的な心筋収縮を引き起こします。

接着接合は動的です

血管の内側を覆う内皮細胞は緊密に結合しており、他の細胞や分子が血流から周囲の組織に漏れ出すのを防ぐ障壁を形成しています。 ただし、免疫応答中、血流からの白血球はこの関門を通過して標的組織に到達する必要があります。 ヒスタミンなどの炎症性分子や血管内皮増殖因子 (VGEF) などのシグナル伝達タンパク質は、内皮細胞表面に存在するカドヘリンのリン酸化や内部移行などの下流プロセスを引き起こします。 これにより、接着結合の分解が起こり、免疫細胞や他の分子が通過できる隙間ができるため、内皮の透過性が高まります。 したがって、接着結合の維持と破壊は、特定の刺激に応答して動的に調節されます。

接着接合部と感染

ヘリコバクター・ピロリのような感染性病原体は、接着結合を破壊し、細胞間ギャップを通って移動することによって宿主組織に侵入する可能性があります。 これらの細菌は、カドヘリンの細胞外ドメインを切断するプロテアーゼを生成し、結合部の分解を引き起こします。 細胞表面カドヘリンは、肺炎球菌などの細菌によっても受容体として乗っ取られ、上気道上皮に付着します。

しかし、最も印象的なハイジャックはおそらくリステリア・モノサイトゲネスによって実証されています。 この細菌は、E-カドヘリンを付着させ、その部位へのα、β、およびp120-カテニンの動員を引き起こす細胞壁タンパク質を発現します。 この動員により動的なアクチン重合が開始され、誘導食作用と呼ばれるプロセスで細菌を飲み込む膜突起が形成されます。 したがって、細菌は非食細胞への侵入を獲得し、宿主内で増殖します。

隣接する細胞間の強い接触点がそれらを互いに固定し、組織を形成します。このようなアンカージャンクションには、接着材...

Education

JoVE Core

Cell Biology

細胞生物学

Unit 1

ユニット1

Cell-Cell Interactions

細胞間相互作用

KEY TERMS AND CONCEPTS

主要用語と概念

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 細胞生物学は、複雑な細胞プロセスを、わかりやすく包括的なアニメーション ビデオ レッスンで説明します。このコレクションは、細胞小器官や膜、細胞輸送、細胞のエネルギー学など、細胞の必須コンポーネントと機能に焦点を当てています。これは、実際の研究実験における細胞生物学の応用を実証する科学者による実際のビデオによって補足されています。

Cell Adhesion in Tissues and Infection

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