Document Detail


Cog2 null mutant CHO cells show defective sphingomyelin synthesis.
MedLine Citation:
PMID:  21047787     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The COG (conserved oligomeric Golgi complex) is a Golgi-associated tethering complex involved in retrograde trafficking of multiple Golgi enzymes. COG deficiencies lead to misorganization of the Golgi, defective trafficking of glycosylation enzymes, and abnormal N-, O- and ceramide-linked oligosaccharides. Here, we show that in Cog2 null mutant ldlC cells, the content of sphingomyelin (SM) is reduced to ∼25% of WT cells. Sphingomyelin synthase (SMS) activity is essentially normal in ldlC cells, but in contrast with the typical Golgi localization in WT cells, in ldlC cells, transfected SMS1 localizes to vesicular structures scattered throughout the cytoplasm, which show almost no signal of co-transfected ceramide transfer protein (CERT). Cog2 transfection restores SM formation and the typical SMS1 Golgi localization phenotype. Adding exogenous N-6-[(7-nitrobenzo-2-oxa-1,3-diazol-4-yl)amino]hexanoyl-4-d-erythro-sphingosine (C(6)-NBD-ceramide) to ldlC cell cultures results in normal SM formation. Endogenous ceramide levels were 3-fold higher in ldlC cells than in WT cells, indicating that Golgi misorganization caused by Cog2 deficiency affects the delivery of ceramide to sites of SM synthesis by SMS1. Considering the importance of SM as a structural component of membranes, this finding is also worth of consideration in relation to a possible contribution to the clinical phenotype of patients suffering congenital disorders of glycosylation type II.
Authors:
Waldo Spessott; Andrea Uliana; Hugo J F Maccioni
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2010-11-03
Journal Detail:
Title:  The Journal of biological chemistry     Volume:  285     ISSN:  1083-351X     ISO Abbreviation:  J. Biol. Chem.     Publication Date:  2010 Dec 
Date Detail:
Created Date:  2010-12-27     Completed Date:  2011-02-09     Revised Date:  2013-07-03    
Medline Journal Info:
Nlm Unique ID:  2985121R     Medline TA:  J Biol Chem     Country:  United States    
Other Details:
Languages:  eng     Pagination:  41472-82     Citation Subset:  IM    
Affiliation:
Departamento de Química Biológica, Facultad de Ciencias Químicas, Centro de Investigaciones en Química Biológica de Córdoba, Universidad Nacional de Córdoba, Ciudad Universitaria, X5000 HUA Córdoba, Argentina.
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MeSH Terms
Descriptor/Qualifier:
Adaptor Proteins, Vesicular Transport / chemistry*
Animals
CHO Cells
Cricetinae
Cricetulus
Gene Expression Regulation
Glycosylation
Golgi Apparatus / metabolism
Microscopy, Confocal / methods
Mutation
Phenotype
Sphingomyelins / chemistry*
Subcellular Fractions / metabolism
Toxins, Biological / chemistry
Transferases (Other Substituted Phosphate Groups) / metabolism
Chemical
Reg. No./Substance:
0/Adaptor Proteins, Vesicular Transport; 0/Sphingomyelins; 0/Toxins, Biological; 0/lysenin; EC 2.7.8.-/Transferases (Other Substituted Phosphate Groups); EC 2.7.8.-/phosphatidylcholine-ceramide phosphocholine transferase
Comments/Corrections

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