class 2 1 Flashcards
Describe the proteins involved in directing physiologicalocyte homing and extravasation during inflammatory processes.
Proteins involved include adhesion molecules, proteases, cytokines, and chemokines.
What are some mechanisms that regulate leukocyte migration?
Mechanisms include up- or down-regulation of chemokine or chemokine receptor gene expression, interaction ofokines with specific glycosaminoglycans, and binding of chemokines to atypical chemokine receptors.
How does modification of the interaction of chemokines with glycosaminoglycans affect chemokine availability?
It alters the presentation of chemokines to chemokine receptors on circulating leukocytes.
Define the mechanisms that fine-tune chemokine function.
These include synergy or antagonism between chemokines, alternative splicing of chemokine genes, and posttranslational modification of chemokines.
Describe the classification of CXC chemokines based on the presence of an ELR motif.
CXC chemokines are subdivided into ELR+ and ELR- CXC chemokines based on the presence of an ELR motif (Glu-Leu-Arg) preceding the CXC sequence.
How are the seven-transmembrane G protein-coupled receptors for chemokines classified?
The seven-transmembrane G protein-coupled receptors for chemokines are classified according to the subclass of chemokines they recognize, including CXCR, CCR, CX3CR, and XCR.
Describe the property of redundancy in leukocyte migration within the chemokine network.
Despite the cell-specific expression of defined chemokine receptors, chemokines display a high degree of redundancy in leukocyte migration, which is the result of recurrent gene duplications during evolution.
How do chemokines counteract each other in the inflammatory response?
Chemokines can counteract each other by reducing the inflammatory response or increasing the selectivity of cell recruitment through heterologous desensitization, internalization, and antagonistic activity for another receptor.
Define alternative splicing in the context of chemokine function.
Alternative splicing in chemokine function refers to the process where the pre-mRNA of several chemokine genes undergoes alternative splicing, generating multiple mRNAs that are translated into different chemokine isoforms.
What are the suggested mechanisms through which coin-induced chemokines can synergize?
The suggested mechanisms include heteromerization of chemokines or chemokine receptors and synergy at the level of signal transduction.
Describe the process of chemokine production and presentation to leukocytes.
Chemokines are produced at the site of infection by local tissue cells and form a concentration gradient by binding to glycosaminoglycan moieties of proteoglycans in the extracellular matrix They pass the endoth cell layer through diffusion transcytosis endothelial DARC glycosaminoglyans
How are chemokines posttranslationally modified, and what impact does this have on their biological activity?
Chemokines can be proteolytically cleaved, glycosylated, and citrullinated, with proteolytic processing predominantly occurring at the NH2-terminal region. These modifications affect the biological activity of the chemokines.
Do chemokines have different functions based on their membrane-bound and soluble isoforms?
Yes, chemokines have disparate biological functions based on their membrane-bound and soluble isoforms, which are determined by proteolytic processing and other modifications.
Describe the interaction between chemokines and their receptors.
Chemokines drive the recruitment specific leukocyte subsets to a site of inflammation by binding to their chemokine receptors.
What are some mechanisms evolved to regulate chemokine availability and function?
Mechanisms such as alternative splicing, posttranslational modifications, and glycosaminoglycan binding regulate chemokine availability and function.
