Name: cell adhesion molecules in tissues
Uploaded: 2023-04-30T11:55:46.000Z
Duration: 1 min 20 s
Channel: JoVE

تفاعلات الخلايا هي نقاط اتصال فيزيائية بين الخلايا المجاورة. إنها تساعد في تماسك الخلايا والسماح بالاتصال عبر الغشاء ، وهو أمر حيوي للأداء المنسق للأنسجة.
تم العثور على تفاعلات الخلايا المستقرة في الأنسجة ، مثل البطانة ، حيث تدعم تنظيم الأنسجة. على العكس من ذلك ، تساعد التفاعلات الأضعف والعابرة على تجنيد الخلايا الحرة ، مثل الخلايا المناعية.
تتحقق تفاعلات الخلايا هذه من خلال بروتينات خاصة لسطح الخلية ، تسمى مجتمعة جزيئات التصاق الخلية أو CAMs.
من بين العائلات الأربع الرئيسية ل CAMs ، تشارك عائلة الإنتجرين في تفاعل الخلية مع المصفوفة خارج الخلية ، بينما تشارك العائلات الثلاث الأخرى في تفاعلات الخلية الخلوية.
الأول هو الكاديرينات ، التي تشكل تفاعلات مستقرة عن طريق ربط الكاديرين المعبر عنها في الخلايا الأخرى.
ثانيا هي الاختيارات. أنها تربط كربوهيدرات معينة على سطح الخلايا الأخرى وتشكل تفاعلات عابرة.
وأخيرا ، تشكل البروتينات الشبيهة بالغلوبولين المناعي التي تنتمي إلى عائلة الغلوبولين المناعي الفائقة أيضا تفاعلات عابرة عن طريق ربط البروتينات والإنتجرينات المماثلة الأخرى بالخلايا الأخرى.

<ol>
	<li>Harjunpää ، Heidi ، et al. "جزيئات التصاق الخلايا وأدوارها وتنظيمها في البيئة المكروية المناعية والورم". الحدود في علم المناعة (2019): 1078.</li>
</ol>

جزيئات التصاق الخلايا - أنواعها ووظائفها

Cell Adhesion Molecules - Types and Functions

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تعتبر جزيئات التصاق الخلايا (CAMs) محورية في تعدد الخلايا والعمل المنسق للأنسجة وأنظمة الأعضاء. أنها تمكن التفاعلات الجسدية بين الخلايا وتوفر القوة الميكانيكية للأنسجة. كما أنها تعمل كمستقبلات لنقل الإشارات عبر غشاء البلازما. يتم تصنيف CAMs على نطاق واسع إلى أربع عائلات - انتغرينات ، وكادهيرينات ، وسيليكتينات، و CAMs الشبيهة بالجلوبيولين المناعي (IgCAMs).

عائلات CAM

تشارك عائلة البروتينات انتغرين Integrin بشكل أساسي في تفاعل الخلية مع النسيج البيني المحيط بها. ومع ذلك، يمكن لبعض الإنتغرينات ربط CAMs على سطح خلية أخرى والمشاركة في التفاعلات المباشرة بين الخلايا. على سبيل المثال، ترتبط الإنتغرينات الموجودة على الخلايا المناعية بـ IgCAMs المعبر عنها في بطانة الأوعية الدموية.

الكادهيرينات هي فصيلة فائقة من الغليكوبروتينات المعتمدة على الكالسيوم والتي تشارك بشكل أساسي في إنشاء التصاقات قوية للخلايا. وهي تشكل الوصلات الملتصقة والديسموسومات في الأنسجة، مثل الظهارة.

تشارك السيليكتينات وIgCAMs في تفاعلات الخلايا العابرة وتشارك في توجيه الخلايا نحو المواقع المستهدفة. على سبيل المثال، فهي تساعد في التجنيد الانتقائي للخلايا الليمفاوية في الأعضاء اللمفاوية الثانوية.

CAMs و تعدد الخلايا

تم العثور على CAMs في جميع الكائنات متعددة الخلايا تقريبًا - بدءًا من الإسفنج والديدان الخيطية البسيطة وحتى اللافقاريات والفقاريات المعقدة. يزداد تعقيد التفاعلات الخلوية، وبالتالي تعقيد CAMs، مع زيادة تعقيد الكائنات الحية. على سبيل المثال، في حين أن ذبابة الفاكهة D.melanogaster لديها ما يقرب من 500 جينة تشارك في التصاق الخلايا، فإن الفقاريات المعقدة مثل الثدييات لديها أكثر من ألف جينة ترمز لأنواع مختلفة من CAMs.
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تعتبر جزيئات التصاق الخلايا (CAMs) محورية لتعدد الخلايا والأداء المنسق للأنسجة وأنظمة الأعضاء. إنها تمكن المادية ...

cell-adhesion-molecules-types-and-functions

Education

JoVE Core

Cell Biology

بيولوجيا الخلية

Unit 1

الوحدة الأولى

Cell-Cell Interactions

التفاعلات بين الخلايا

KEY TERMS AND CONCEPTS

المصطلحات والمفاهيم الأساسية

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 others help cells make short-lived contacts and move to the right place.

Integrins mainly help a cell interact with the surrounding matrix, which is the material around cells. Some integrins can also bind CAMs on another cell and take part in direct cell-cell contact. For example, integrins on immune cells bind IgCAMs on the vascular endothelium, the inner lining of blood vessels.

Cadherins are calcium-dependent glycoproteins. They are known for strong cell adhesion and help form adherens junctions and desmosomes in tissues such as epithelium. Selectins and IgCAMs usually support transient cell interactions. They also help guide cells to target sites, such as the selective recruitment of lymphocytes to secondary lymphoid organs.

CAMs are found in nearly all multicellular organisms, from sponges and simple nematodes to complex invertebrates and vertebrates. As organisms become more complex, their cell interactions and CAM systems also become more complex. For example, D. melanogaster has about 500 genes involved in cell adhesion, while mammals have over a thousand genes that code for different CAMs.

Cell Adhesion Molecules in Tissues

cell adhesion molecules - types and functions

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

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 cell adhesion molecules help tissues stay strong, guide immune cells, and support cell signaling through four major CAM families.

Cell Adhesion Molecules 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 Adhesion Molecules in Tissues

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