Ligand-induced changes in integrin expression regulate neuronal adhesion and neurite outgrowth.
Receptors of the integrin family are expressed by every cell type and are the primary means by which cells interact with the extracellular matrix. The control of integrin expression affects a wide range of developmental and cellular processes, including the regulation of gene expression, cell adhesion, cell morphogenesis and cell migration. Here we show that the concentration of substratum-bound ligand (laminin) post-translationally regulates the amount of receptor (alpha6beta1, integrin) expressed on the surface of sensory neurons. When ligand availability is low, surface amounts of receptor increase, whereas integrin RNA and total integrin protein decrease. Ligand concentration determines surface levels of integrin by altering the rate at which receptor is removed from the cell surface. Furthermore, increased expression of integrin at the cell surface is associated with increased neuronal cell adhesion and neurite outgrowth. These results indicate that integrin regulation maintains neuronal growth-cone motility over a broad range of ligand concentrations, allowing axons to invade different tissues during development and regeneration.
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Department of Neurobiology and Anatomy, University of Utah, School of Medicine, Salt Lake City 84132, USA. maureenc@mailman.med.utah.edu
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D000818:Animals; D002448:Cell Adhesion; D002455:Cell Division / Q000502:physiology; D002462:Cell Membrane / Q000378:metabolism; D002465:Cell Movement / Q000502:physiology; D002478:Cells, Cultured; D002642:Chick Embryo; D005109:Extracellular Matrix / Q000378:metabolism; D005727:Ganglia, Spinal / Q000166:cytology / Q000378:metabolism; D005786:Gene Expression Regulation; D039121:Integrin alpha6beta1; D016023:Integrins / Q000096:biosynthesis* / Q000235:genetics; D007797:Laminin / Q000378:metabolism; D008024:Ligands; D016501:Neurites / Q000502:physiology*; D009474:Neurons / Q000502:physiology*; D012333:RNA, Messenger / Q000378:metabolism; D017474:Receptors, Laminin / Q000096:biosynthesis* / Q000235:genetics
D039121:Integrin alpha6beta1; D016023:Integrins; D007797:Laminin; D008024:Ligands; D012333:RNA, Messenger; D017474:Receptors, Laminin