Name: catenins in cell junctions and signaling
Uploaded: 2023-04-30T11:55:07.000Z
Duration: 1 min 23 s
Channel: JoVE

카테닌은 세포-세포 접착에 참여하는 다양한 어댑터 단백질 그룹입니다.
카테닌은 cadherins, cytoskeletal components 및 다양한 cytoskeletal regulator protein과 결합하는 여러 결합 도메인을 가지고 있습니다. 따라서, 그들은 세포 접착 부위에서 세포골격을 cadherin과 연결합니다.
플라코글로빈(plakoglobin) 및 플라코필린(plakophilin)과 같은 일부 카테닌(catenin)은 카드헤린(cadherin)과 중간 필라멘트 사이의 안정적인 연결을 설정하는 데 도움이 되는 반면, 알파 및 베타 카테닌(beta-catenin)과 같은 다른 카테닌은 원형질막(plasma membrane)에서 액틴 세포골격(actin cytoskeleton)을 동적으로 조직합니다.
액틴 필라멘트의 조직은 베타-카테닌이 카데린 분자의 세포질 도메인에 결합하는 것으로 시작됩니다. 그 후, 알파-카테닌은 베타-카테닌에 결합합니다.
또 다른 카테닌(catenin)인 p120 역시 이러한 복합체에 묶여 막에 있는 카데린(cadherin)의 안정성을 조절합니다.
몇 개의 cadherin-catenin 복합체가 함께 클러스터링됨에 따라 alpha-catenin은 해리되어 세포질 이량체를 형성합니다.
이 알파-카테닌 이량체는 사상(filamentous actin)과 강력하게 상호 작용하고 액틴 다발을 구성하는 데 도움을 주어 세포 접착 부위에 세포골격 강도를 제공합니다.

<ol>
	<li>페레즈-모레노, 미르나, 일레인 푹스. "카테닌: 세포가 신호를 교차하지 못하도록 보호." 발달 세포 11.5 (2006): 601-612.</li>
	<li>Moon, Randall T. "Wnt/β-catenin pathway." Science's STKE 2005.271 (2005): cm1-cm1.</li>
</ol>

카테닌

Catenins

카테닌은 세포 접합 복합체에서 링커 단백질로 기능할 수 있도록 하는 다중 결합 도메인과 동적 구조를 특징으로 합니다. α-카테닌을 제외한 모든 카테닌은 아르마딜로 반복이라는 특징적인 단백질 서열을 포함하므로 아르마딜로 단백질이라고도 합니다.

세포 접합의 카테닌

카테닌은 카드헤린과 같은 세포 접착 분자에 결합하여 세포 접합 유형에 따라 이를 다른 세포골격 단백질에 연결합니다. 부착 접합부에서 액틴 세포골격은 알파-, 베타- 및 p120-카테닌에 의해 직접 또는 간접적으로 동적으로 구성됩니다. 예를 들어, α-카테닌은 F-액틴에 직접 결합하는 반면, p120은 Rho GTPases를 통해 액틴 중합을 조절합니다. 그러나 데스모솜에서 중간 필라멘트는 플라코글로빈 및 플라코필린이라는 특수 카테닌과 데스모플라킨과 같은 다른 단백질의 상호작용에 의해 구성됩니다.

β-카테닌과 세포 신호전달

세포 접합부에서 카드헤린과 결합하는 것 외에도 β-카테닌은 Wnt 경로와 같은 세포 신호 전달에도 기능할 수 있습니다. 이 경로에서, frizzled라고 불리는 세포 표면 수용체에 Wnt 신호 분자가 결합하면 세포질에서 β-카테닌 농도를 증가시키는 연쇄반응이 촉발됩니다. 이는 β-카테닌이 핵으로 이동하고, 전사 인자에 결합하고, 표적 유전자 발현을 조절하는 것을 허용합니다. 유기체 전체에 걸쳐 여러 조직 특이적 변종을 갖는 다른 카테닌과 달리, β-카테닌의 단일 변종만이 척추동물에서 발견됩니다. 이 변종은 모든 척추동물 종에 걸쳐 고도로 보존된 아미노산 서열로 구성됩니다.

p120-카테닌과 시냅스 가소성

카드헤린-카테닌 복합체는 기억과 관련된 시냅스 연결을 강화하고 약화시키는 시냅스 가소성의 중요한 부분입니다. 예를 들어, p120은 시냅스 막의 글루타메이트 수용체 안정화에 관여하여 장기간 강화를 유지합니다. 또한 세포내이입을 방지하고 시냅스 접합부에서 카드헤린 클러스터링을 촉진하여 신경 카드헤린의 안정화에도 관여합니다. p120을 하향조절하면 시냅스 전 뉴런과 시냅스 후 뉴런 사이의 접착을 방지하는 것으로 나타났습니다.

카테닌은 세포 접합 복합체에서 링커 단백질로 기능할 수 있도록 하는 여러 결합 도메인과 동적 구조를 특징으로 합니다. ...

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

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 depends on the type of cell junction. At adherens junctions, alpha-catenin, beta-catenin, and p120-catenin help organize the actin cytoskeleton. Alpha-catenin binds directly to F-actin. p120 helps control actin polymerization through Rho GTPases.

At desmosomes, catenins help organize intermediate filaments instead of actin. In this case, special catenins called plakoglobin and plakophilin interact with other proteins such as desmoplakin. These interactions help build strong cell connections in tissues that need mechanical support.

Beta-catenin also has a signaling role in the Wnt pathway. When a Wnt signal molecule binds to the frizzled receptor on the cell surface, a cascade raises beta-catenin levels in the cytoplasm. Beta-catenin can then move into the nucleus, bind to transcription factors, and regulate target gene expression. In vertebrates, only one beta-catenin variant is found, and its amino acid sequence is highly conserved across species.

p120-catenin also plays an important role in synaptic plasticity, which is the strengthening and weakening of synaptic connections involved in memory. It helps stabilize glutamate receptors on the synaptic membrane and supports long-term potentiation. p120 also stabilizes neural cadherins by preventing their endocytosis and by promoting cadherin clustering at synaptic junctions. When p120 is downregulated, adhesion between pre- and postsynaptic neurons is reduced.

Catenins in Cell Junctions and Signaling

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 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

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

Explore how catenins link cadherins to the cytoskeleton, support Wnt signaling, and help strengthen synapses in high school biology.

Catenins in Cell Junctions and Signaling | 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.

Catenins in Cell Junctions and Signaling

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