title: Long-term potentiation of exocytosis and cell membrane repair in fibroblasts.
abstract: We previously found that a microdisruption of the plasma membrane evokes Ca(2+)-regulated exocytosis near the wound site, which is essential for membrane resealing. We demonstrate herein that repeated membrane disruption reveals long-term potentiation of Ca(2+)-regulated exocytosis in 3T3 fibroblasts, which is closely correlated with faster membrane resealing rates. This potentiation of exocytosis is cAMP-dependent protein kinase A dependent in the early stages (minutes), in the intermediate term (hours) requires protein synthesis, and for long term (24 h) depends on the activation of cAMP response element-binding protein (CREB). We were able to demonstrate that wounding cells activated CREB within 3.5 h. In all three phases, the increase in the amount of exocytosis was correlated with an increase in the rate of membrane resealing. However, a brief treatment with forskolin, which is effective for short-term potentiation and which could also activate CREB, was not sufficient to induce long-term potentiation of resealing. These results imply that long-term potentiation by CREB required activation by another, cAMP-independent pathway.
authors.affiliation: Department of Molecular and Cell Biology, University of California, Berkeley, California 94720-3200, USA.
authors.forename: Tatsuru
authors.initials: T
authors.lastname: Togo
authors.forename: Janet M
authors.initials: JM
authors.lastname: Alderton
authors.forename: Richard A
authors.initials: RA
authors.lastname: Steinhardt
mesh_terms: D016475:3T3 Cells; D000818:Animals; D020126:Brefeldin A / Q000378:metabolism; D002462:Cell Membrane / Q000502:physiology*; D017362:Cyclic AMP Response Element-Binding Protein / Q000378:metabolism; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D005089:Exocytosis / Q000502:physiology*; D005347:Fibroblasts / Q000502:physiology*; D051379:Mice; D011493:Protein Kinase C / Q000378:metabolism; D013997:Time Factors
chemical_list: D017362:Cyclic AMP Response Element-Binding Protein; D020126:Brefeldin A; D017868:Cyclic AMP-Dependent Protein Kinases; D011493:Protein Kinase C