Related Experiment Video
Updated: Jun 7, 2026
18:25
Live Imaging Assay for Assessing the Roles of Ca2+ and Sphingomyelinase in the Repair of Pore-forming Toxin Wounds
Published on: August 25, 2013
Cog2 null mutant CHO cells show defective sphingomyelin synthesis.
Waldo Spessott1, Andrea Uliana, Hugo J F Maccioni
1Departamento 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.
The Journal of Biological Chemistry
|November 5, 2010
Summary
Conserved oligomeric Golgi complex (COG) deficiency disrupts sphingomyelin (SM) production by mislocalizing SM synthase. Restoring COG function normalizes SM levels and enzyme localization, impacting glycosylation disorders.
Area of Science:
- Cell Biology
- Molecular Biology
- Biochemistry
Background:
- The conserved oligomeric Golgi complex (COG) is crucial for retrograde trafficking and Golgi organization.
- COG deficiencies cause Golgi misorganization and defects in glycosylation.
- Sphingomyelin (SM) is a vital membrane structural component synthesized by sphingomyelin synthase (SMS).
Purpose of the Study:
- To investigate the impact of COG deficiency on sphingomyelin synthesis and localization.
- To elucidate the role of COG2 in sphingomyelin production and sphingomyelin synthase 1 (SMS1) trafficking.
- To understand the link between COG function, ceramide delivery, and SM formation.
Main Methods:
- Utilized Cog2 null mutant ldlC cells and wild-type (WT) cells.
- Assessed sphingomyelin (SM) content and sphingomyelin synthase (SMS) activity.
- Examined the localization of transfected SMS1 and ceramide transfer protein (CERT) using immunofluorescence.
- Supplemented ldlC cells with exogenous N-6-[(7-nitrobenzo-2-oxa-1,3-diazol-4-yl)amino]hexanoyl-4-d-erythro-sphingosine (C(6)-NBD-ceramide).
Main Results:
- Cog2 deficiency in ldlC cells reduced SM content to approximately 25% of WT levels.
- Transfected SMS1 exhibited aberrant cytoplasmic localization in ldlC cells, with minimal co-localization with CERT.
- Cog2 transfection restored normal SM formation and SMS1 Golgi localization.
- Exogenous ceramide supplementation normalized SM formation in ldlC cells, despite elevated endogenous ceramide levels.
Conclusions:
- COG deficiency impairs SM synthesis by disrupting ceramide delivery to SMS1 at the Golgi.
- Golgi misorganization due to COG deficiency affects sphingolipid metabolism.
- These findings suggest a potential contribution of COG-related defects to the clinical phenotypes of congenital disorders of glycosylation type II.
