Name: cell junctions in tissues
Uploaded: 2023-04-30T11:54:51.000Z
Duration: 1 min 14 s
Channel: JoVE

세포 접합은 세포-기질 접합을 형성하는 세포외 기질에 세포를 연결하거나 조직의 인접 세포 간의 접촉점 역할을 하여 세포-세포 접합을 형성할 수 있는 대규모 다중 단백질 복합체입니다.
세포는 일반적으로 세 가지 주요 유형의 세포-세포 연접(tight, anchoring 및 gap junction)을 가지고 있으며, 각각 고유한 구조와 기능을 가지고 있습니다.
원주형 상피를 생각해 보십시오. 이 세포의 정점 근처의 긴밀한 연접은 인접한 원형질막을 함께 고정하고 세포 간 공간을 통한 분자의 흐름에 대한 장벽으로 기능합니다.
이 정점 부분 아래에는 두 가지 유형의 앵커링 접합(anchoring junctions)이 있습니다 - adherens junctions 및 desmosomes.
이러한 앵커링 연접은 함께 세포 전체에 걸쳐 상호 연결된 세포골격 네트워크를 형성하여 기계적 힘에 저항하는 데 도움이 됩니다.
세 번째 유형인 간극연접(gap junctions)은 원형질막 전체, 특히 기저 말단부에 분산되어 있습니다. 이러한 접합부는 인접한 세포 사이의 통신 채널 역할을 하여 분자와 이온이 통과할 수 있도록 합니다.

<ol>
	<li>캠벨, 한나 K., 제시카 L. 마이어스, 크리스 A. 드말리. "밀접 접합과 접착 접합 간의 상호 작용." 실험 세포 연구 358.1 (2017): 39-44.</li>
	<li>Giepmans, Ben NG. "간극 연접 및 커넥신 상호 작용 단백질." 심혈관 연구 62.2 (2004) : 233-245.</li>
</ol>

세포-세포연접

Overview of Cell-Cell Junctions

모든 다세포 유기체에서 세포의 복잡한 3차원 배열은 세포 간 및 세포외 기질과의 상호작용에 의해 정의되고 유지됩니다. 세포-세포 연접은 한 세포의 다중 단백질 복합체가 다른 세포의 다중 단백질 복합체와 상호 작용하는 특수 구조입니다. 이러한 세포연접은 기능에 따라 밀착, 고정 및 간격연접의 세 가지 주요 유형으로 분류됩니다.

밀착연접

밀착연접은 주로 세포간 공간을 통한 물 및 용질과 같은 분자의 이동을 방지하는 기능을 합니다. 이는 인접한 막의 동일한 단백질과 직접 상호작용하는 일련의 막횡단 단백질로 존재합니다. 따라서 이는 두 개의 원형질막을 서로 가깝게 유지하여 분자의 통과를 방지합니다. 밀착연접은 또한 선택적으로 투과성이 있어 전하 특정 이온은 통과하는 동시에 다른 이온은 차단할 수 있습니다.

고정연접

고정연접은 세포를 함께 고정하고 조직 구조에 기계적 강도를 제공합니다. 이는 한 세포의 세포골격이 카드헤린이라고 불리는 막횡단 접착 분자를 통해 이웃 세포의 세포골격에 고정되는 접촉점을 형성합니다. 고정연접에는 두 가지 유형이 있습니다.

<ol style="list-style-type: circle;">
	<li>액틴 세포골격과 액틴 세포골격을 연결하는 연접점을 부착함.</li>
	<li>중간 필라멘트를 연결하는 부착반점.</li>
</ol>

따라서 이는 조직 구조와 기능을 유지하기 위해 협력적으로 기능하는 광범위한 세포골격 네트워크를 형성합니다.

간극연접

간극연접은 세포 간 통신을 촉진하는 단백질 채널입니다. 구성 막횡단 단백질은 인접한 세포의 세포질을 연결하는 채널을 형성하고 분자 및 전기 자극의 교환을 허용합니다. 분자의 이동은 채널 단백질의 개폐에 의해 조절됩니다. 예를 들어, 심장의 리듬 수축에 대한 신호는 심장 근육 조직의 간극연접을 통해 세포에서 세포로 전달됩니다. 그러나 식물세포는 세포벽 때문에 간극연접을 통해 분자를 교환할 수 없습니다. 대신에 이는 플라스모데스마타라고 불리는 의사소통 채널을 형성합니다. 이는 한 세포의 세포질이 다른 세포의 세포질과 인접하도록 세포벽을 통해 세포를 연결하는 막으로 둘러싸인 구멍입니다. 따라서 플라스모데스마타로 연결된 식물 세포를 통해 용질과 이온의 자유로운 이동이 있습니다.

모든 다세포 유기체에서 세포의 복잡한 3차원 배열은 세포가 서로 상호 작용하고 ...

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 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 occluding junctions, stop water and solutes from moving through the spaces between cells. They do this with transmembrane proteins that match and bind to the same proteins on the adjacent cell membrane, keeping the two membranes close together. Tight junctions can also be selectively permeable, so some charge-specific ions can pass while others are blocked.

Anchoring junctions give tissues mechanical strength by holding cells together. They create contact points where the cytoskeleton of one cell attaches to the cytoskeleton of a neighboring cell through transmembrane adhesion molecules called cadherins. Two main forms are adherens junctions, which link actin filaments, and desmosomes, which link intermediate filaments. Together, these connections build a strong cytoskeletal network that supports tissue structure and function.

Gap junctions are channels that let cells communicate with each other. Their transmembrane proteins form a passage between the cytoplasms of adjacent cells, allowing molecules and electrical impulses to move across. The channels can open and close to control movement. In cardiac muscle, gap junctions help pass the signal for rhythmic heart contractions from cell to cell.

Plant cells do not use gap junctions because of the cell wall. Instead, they connect through plasmodesmata, which are membrane-lined pores that pass through the cell walls. These channels link the cytoplasm of one plant cell to another, allowing solutes and ions to move freely between them.

Cell Junctions in Tissues

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 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 tight junctions, anchoring junctions, and gap junctions help cells stay connected, strengthen tissues, and pass signals in animals and plants.

Cell Junctions in Tissues | 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 Junctions in Tissues

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