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Static Adhesion Assay for the Study of Integrin Activation in T Lymphocytes
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Estructura de la integrina, una glicoproteína involucrada en el enlace transmembrana entre la fibronectina y la
Cell
|July 18, 1986
Resumen
Los investigadores identificaron un nuevo complejo de glicoproteínas de membrana, la integrina, crucial para conectar la matriz extracelular con el citoesqueleto. Esta proteína presenta dominios estructurales únicos y un sitio potencial de fosforilación, destacando su papel en la adhesión celular.
Área de la Ciencia:
- Biología celular Biología celular.
- Biología Molecular Biología Molecular
- La bioquímica es la bioquímica.
Sus antecedentes:
- La matriz extracelular (ECM) y el citoesqueleto interactúan para mantener la estructura y la función celular.
- Comprender los mecanismos moleculares de esta conexión transmembrana es vital para la biología celular.
Objetivo del estudio:
- Para aislar, caracterizar y secuenciar clones de ADNc que codifican una subunidad del complejo de conexión ECM-citoesqueleto.
- Proponer un nombre y aclarar las características estructurales y las funciones potenciales de este complejo proteico.
Principales métodos:
- Aislamiento y caracterización de clones de ADNc.
- Secuenciación del ADN para determinar la secuencia del polipéptido.
- Análisis bioinformático de la estructura codificada del polipéptido.
Principales resultados:
- ADNc identificado y secuenciado que codifica una subunidad de polipéptido de 89 kDa.
- El polipéptido posee un gran dominio extracelular con una nueva repetición rica en cisteína, un segmento transmembrana y un pequeño dominio citoplasmático.
- El dominio citoplasmático contiene un sitio potencial de fosforilación de tirosina.
Conclusiones:
- Propuso el nombre de "integrina" para este complejo de proteínas de membrana integral.
- La integrina juega un papel clave en la asociación transmembrana entre el ECM y el citoesqueleto.
- Las características estructurales sugieren roles funcionales en la adhesión celular y la señalización.
Videos de Conceptos Relacionados
01:11Formation of Higher-order Actin Filaments
The polymerization of G-actin monomers into filamentous F-actin is a multi-step process. Once the F-actins are formed, they can bundle together in different arrangements to form higher-order networks and regulate cellular functions. Common examples include the formation of lamellipodia and filopodia at the cell's leading edge by actin reorganization in a migrating cell. The microvilli on the brush border epithelial cells are also formed through the F-actin network.
The high-order actin networks...
The high-order actin networks...
01:25Fibronectins Connect Cells with ECM
Fibronectin is an adhesive glycoprotein present in the extracellular matrix of embryogenic and adult tissue. These molecules primarily aid in regulating cell motility and attachment. A fibronectin molecule is composed of two identical polypeptide chains attached to each other by a pair of disulfide bonds at the C-terminal.
Both proteoglycans and collagen are attached to fibronectin proteins, which, in turn, are attached to integrin proteins. These integrin proteins interact with transmembrane...
Both proteoglycans and collagen are attached to fibronectin proteins, which, in turn, are attached to integrin proteins. These integrin proteins interact with transmembrane...
01:10Integrins
Animal and protozoan cells do not have cell walls to help maintain shape and provide structural stability. Instead, these eukaryotic cells secrete a sticky mass of carbohydrates and proteins into the spaces between adjacent cells. This network of proteins and molecules is called an extracellular matrix or ECM.
Some ECM proteins assemble into a basement membrane to which the remaining components adhere. Proteoglycans typically form the bulk of the ECM while fibrous proteins, like collagen,...
Some ECM proteins assemble into a basement membrane to which the remaining components adhere. Proteoglycans typically form the bulk of the ECM while fibrous proteins, like collagen,...
01:15Activation of Integrins
Integrins bind ligands and transmit information from outside the cell to inside or vice-versa through an "outside-in signaling" or "inside-out signaling."
In "outside-in signaling," external factors in the extracellular space bind to exposed ligand binding sites on integrins. This causes the inactive protein to undergo a conformational change to become active. Integrins are often clustered on the cell membrane. Repetitive and regularly spaced ligand binding events provide an effective stimulus.
In "outside-in signaling," external factors in the extracellular space bind to exposed ligand binding sites on integrins. This causes the inactive protein to undergo a conformational change to become active. Integrins are often clustered on the cell membrane. Repetitive and regularly spaced ligand binding events provide an effective stimulus.
01:17Intracellular Signaling Affects Focal Adhesions
Integrins act both as extracellular input receivers and as intracellular processing activators. As their name suggests, integrins are entirely integrated into the membrane structure. Their hydrophobic membrane-spanning regions interact with the phospholipid bilayer's hydrophobic region. These membrane receptors provide extracellular attachment sites for effectors like hormones and growth factors. They activate intracellular response cascades when their effectors are bound and active.
Some...
Some...
01:03Anchoring Junctions
Anchoring junctions are multiprotein complexes that help cells connect to other cells and the extracellular matrix. Anchoring junctions are present on the lateral and basal surfaces of cells, providing strong and flexible connections. Focal adhesions are often formed due to cell interactions with the ECM substrata, which initiate signal transduction via kinase cascades and other mechanisms. Together, they provide stability and tissue integrity. There are three types of anchoring junctions:...