In the adult @entity1 brain, normal astrocytes constitute nearly 40% of the total central nervous system (CNS) cell population and may assume a star-shaped configuration resembling epithelial cells insofar as the astrocytes remain intimately associated, through their cytoplasmic extensions, with the basement membrane of the capillary endothelial cells and the basal lamina of the glial limitans externa. Although their exact function remains unknown, in the past, astrocytes were thought to subserve an important supportive role for neurons, providing a favorable ionic environment, modulating extracellular levels of neurotransmitters, and serving as spacers that organize neurons. In immunohistochemical preparations, normal, reactive, and neoplastic astrocytes may be positively identified and distinguished from other CNS cell types by the expression of the astrocyte-specific intermediate filament @entity538 ( @entity538 ). @entity538 is a 50-kD intracytoplasmic filamentous protein that constitutes a portion of, and is specific for, the cytoskeleton of the astrocyte. This protein has proved to be the most specific marker for cells of astrocytic origin under normal and pathological conditions. Interestingly, with increasing @entity5 , there is progressive loss of @entity538 production. As the @entity1 gene for @entity538 has now been cloned and sequenced, this review begins with a summary of the molecular biology of @entity538 including the proven utility of the @entity538 promoter in targeting genes of interest to the CNS in transgenic animals. Based on the data provided the authors argue cogently for an expanded role of @entity538 in complex cellular events such as cytoskeletal reorganization, maintenance of myelination, cell adhesion, and signaling pathways. As such, @entity538 may not represent a mere mechanical integrator of cellular space, as has been previously thought. Rather, @entity538 may provide docking sites for important kinases that recognize key cellular substrates that enable @entity538 to form a dynamic continuum with microfilaments, integrin receptors, and the extracellular matrix.

Role of glial filaments in cells and XXXX of glial origin: a review.

@entity1 :: ('9606', 'Species') :: ['human'] @entity5 :: ('MESH:D009369', 'Disease') :: ['astrocytic malignancy'] @entity538 :: ('2670', 'Gene') :: ['GFAP', 'glial fibrillary acidic protein', 'Glial fibrillary acidic protein']
@entity5 :: (MESH:D009369,Disease) :: ['tumors']
