Document Detail

Rapid desensitization of PC12 cells stimulated with high concentrations of extracellular S100.
MedLine Citation:
PMID:  10199630     Owner:  NLM     Status:  MEDLINE    
Undifferentiated PC12 cells undergo apoptosis, via a calcium-induced calcium release mechanism, when the calcium-binding protein purified from bovine brain (native S100) is present in micromolar concentration in the medium. This process begins when S100 binds to specific membrane binding sites and involves up to 50% of the cell population. In the experiments reported here, we demonstrate that, by utilizing [3H]S100, the S100 protein can be displaced from its binding sites only during the first 10 min of incubation. This fact is due to an internalization mechanism, having a time-course with a plateau after 10-20 min of incubation. The native form of S100 is a mixture of two different S100 isoforms: S100A1 (20%) and S100B (80%). Using confocal microscopy and monoclonal antibodies, we demonstrated that only one of these isoforms, S100A1, was autoexpressed in more than 50% of the PC12 cells analysed. After cell incubation with 2 microM native S100, S100B also appears in PC12 cells, with a maximum presence after 10 min of incubation. This fact seems to indicate that this isoform, at least, is effectively translocated when stimulated with external native S100. From the data reported, it is possible to hypothesize that, in PC12 cells, a possible homeostatic mechanism is present that can counteract the effect of a continuously applied lethal stimulus (stimuli) on cell viability.
S Fulle; M A Mariggiò; S Belia; C Petrelli; P Ballarini; S Guarnieri; G Fanò
Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Neuroscience     Volume:  89     ISSN:  0306-4522     ISO Abbreviation:  Neuroscience     Publication Date:  1999 Mar 
Date Detail:
Created Date:  1999-07-07     Completed Date:  1999-07-07     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  7605074     Medline TA:  Neuroscience     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  991-7     Citation Subset:  IM    
Dipartimento di Biologia Cellulare e Molecolare, Università di Perugia, Italy.
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MeSH Terms
Apoptosis / drug effects*
Binding Sites
Calcium Signaling / drug effects*,  physiology
Microscopy, Confocal
Neoplasm Proteins / biosynthesis,  genetics
PC12 Cells / drug effects*
Protein Isoforms / biosynthesis,  genetics,  pharmacology*
S100 Proteins / biosynthesis,  classification,  genetics,  pharmacology*
Reg. No./Substance:
0/Neoplasm Proteins; 0/Protein Isoforms; 0/S100 Proteins

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