Name: cell communication through gap junctions
Uploaded: 2023-04-30T11:55:54.000Z
Duration: 1 min 27 s
Channel: JoVE

간극연접(gap junction)은 인접한 동물 세포 사이의 통신 채널입니다.
이 채널은 커넥신(connexin)이라고 하는 막관통 단백질로 구성되어 있습니다. 6개의 커넥신 분자가 커넥슨(connexon)이라고 하는 반채널을 형성합니다.
호질머릭 커넥슨(homomeric connexon)은 동일한 커넥신(connexin) 단백질의 6개 사본으로 구성되는 반면, 헤테로메릭 커넥슨(heteromeric connexon)은 서로 다른 커넥신 단백질에 의해 형성됩니다.
커넥슨은 멤브레인을 통해 동적으로 확산될 수 있습니다. 세포막의 한 커넥손이 인접한 세포의 다른 커넥슨을 만나면 쌍을 이루어 완전한 채널을 형성합니다.
이러한 채널의 클러스터는 세포 간에 이온, 2차 전달자, 당 및 기타 작은 분자의 교환을 허용하는 간극 연접 플라크를 형성합니다.
커넥신(connexin)과 그 조합의 다양성은 특정 분자에 대한 채널 선택성을 부여합니다.
용질의 수송은 전압 차이, 칼슘 이온 농도 및 pH와 같은 다양한 자극에 대한 반응으로 채널의 개폐에 의해 더욱 조절됩니다.
예를 들어, 심장 근육의 간극연접은 전압 차이에 반응하고 근육 세포 그룹 간의 이온 흐름을 동기화하여 심장에 리드미컬한 수축을 생성합니다.

<ol>
	<li>Laird, Dale W. "건강과 질병에서 커넥신의 수명주기." 생화학 저널 394.3 (2006) : 527-543.</li>
	<li>Bauer, Reinhard, et al. "세포 간 통신 : 간극 연접 단백질의 Drosophila innexin 다중 단백질 제품군." 화학 및 생물학 12.5 (2005) : 515-526.</li>
	<li>Sager, Ross E., and Jung-Youn Lee. "Plasmodesmata at a glance." 세포과학저널 131.11 (2018): jcs209346.</li>
</ol>

간극연접

Gap Junctions

인접한 동물 세포의 세포질은 간극연접을 형성하는 통신 채널을 통해 소분자, 이온 및 2차 전달자를 교환할 수 있습니다. 이러한 접합은 수백에서 수천 개의 분자 채널로 구성되며, 각각은 코넥신 반채널이라고 불리는 두 개의 반쪽으로 구성됩니다. 코넥신은 6개의 막횡단 코넥신 단백질로 구성된 6량체로, 방사상으로 조립되어 중앙에 구멍이나 채널을 형성합니다. 하나의 코넥신 반채널은 인접한 셀의 해당 커넥슨과 도킹하여 채널을 완성합니다.

간극연접 역학

코넥신은 거친 소포체의 리보솜에 의해 번역되고 동시에 ER 막에 삽입됩니다. 그런 다음 단량체는 골지 네트워크로 이동하여 올리고머화됩니다. 6량체 연결은 분비 소포를 통해 트랜스-골지 네트워크에서 원형질막으로 운반됩니다. 코넥신은 다른 코넥신과 만나 클러스터를 형성할 때까지 원형질막을 따라 자유롭게 이동할 수 있습니다. 따라서 성장하는 클러스터에는 주변에 지속적으로 새로운 코넥신이 추가되어 간격 접합 플라크가 형성됩니다. 이 플라크의 중앙에는 오래된 코넥신이 세포내이입되고 분해된 것으로 표시됩니다. 따라서 간극연접은 막에서 코넥신의 지속적인 회전율을 갖는 동적 조립체입니다.

무척추동물 간극연접

무척추동물의 간극연접은 척추동물과 유사한 구조를 가지고 있습니다. 그러나 이는 인넥신(무척추동물 코넥신)이라고 불리는 다른 단백질로 구성됩니다. 인넥신은 유사한 막횡단 구조를 가지고 있지만 코넥신과 서열 상동성을 공유하지 않습니다. 이는 또한 인넥신 헤미채널을 형성하기 위해 6개가 아닌 8개의 단위가 필요하다는 점에서 척추동물과 다릅니다.

식물의 대응물

인접한 세포막이 직접 접촉하는 동물 조직과 달리 식물 조직의 세포벽은 인접한 원형질막과 직접적인 접촉을 방지합니다. 따라서 세포간 통신과 분자 교환은 형질모세포라고 불리는 특수 접합을 통해 발생합니다. 한 세포의 막은 이러한 접합부에서 인접한 세포의 막과 연속되어 있으며 직경이 약 20~40nm인 관형 채널을 형성합니다. 따라서 인접한 세포의 세포질은 연속되어 있어 다양한 소분자의 교환이 조절됩니다.

인접한 동물 세포의 세포질은 간극을 형성하는 통신 채널을 통해 작은 분자, 이온 및 2 차 메신저를 교환 할 수 있습니다 ...

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 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 connexon from one cell docks with a matching connexon from the neighboring cell to complete the channel.

Connexins are made on ribosomes attached to the rough endoplasmic reticulum. They are inserted into the ER membrane as they are made. The monomers then move to the Golgi network, where they oligomerize, or assemble into larger units. The hexameric connexons travel from the trans-Golgi network to the plasma membrane in secretory vesicles.

Once at the membrane, connexons can move freely until they meet other connexons. They cluster together and form a gap junction plaque. New connexons keep joining at the outer edge of the plaque. At the center, older connexons are endocytosed and marked for degradation, so gap junctions keep turning over over time.

Invertebrate gap junctions are similar in shape to vertebrate ones, but they use different proteins called innexins. Innexins are not sequence homologs of connexins, even though they have a similar transmembrane structure. They also form hemichannels with eight units instead of six.

Plants use plasmodesmata instead of gap junctions because their cell walls keep adjacent plasma membranes from touching directly. These junctions allow intercellular communication and the exchange of molecules between plant cells. The membrane of one cell continues into the next, forming a tubular channel about 20 to 40 nm wide. This makes the cytoplasm of neighboring cells continuous and allows the regulated movement of small molecules.

Cell Communication Through Gap Junctions

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

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

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 gap junctions connect animal cells, how connexins build connexon channels, and how innexins and plasmodesmata support cell communication.

Cell Communication Through Gap Junctions | 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 Communication Through Gap Junctions

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