Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Review
. 2009 Jul;55(1):1-9.
doi: 10.1016/j.jdermsci.2009.04.006. Epub 2009 May 13.

A possible mechanism underlying the ceramide deficiency in atopic dermatitis: expression of a deacylase enzyme that cleaves the N-acyl linkage of sphingomyelin and glucosylceramide

Genji Imokawa  1
Affiliations
Review

A possible mechanism underlying the ceramide deficiency in atopic dermatitis: expression of a deacylase enzyme that cleaves the N-acyl linkage of sphingomyelin and glucosylceramide

Genji Imokawa. J Dermatol Sci. 2009 Jul.

Abstract

A deficiency of ordinary ceramides in the stratum corneum is an essential etiologic factor for the dry and barrier-disrupted skin of patients with atopic dermatitis (AD). We have proposed that the mechanism underlying that deficiency involves a novel sphingolipid metabolizing enzyme, termed sphingomyelin (SM) glucosylceramide (GCer) deacylase, which hydrolyzes SM or GCer at the acyl site to yield their lysoforms sphingosylphosphorylcholine (SPC) or glucosylsphingosine (GSP) instead of ceramide, leading to the ceramide deficiency in the AD skin. The enzymic characteristics observed showed a pH dependency of catalytic activity with a peak at pH 5.0 and a molecular weight of 40,000. Analytical isoelectric focusing (IEF) chromatography demonstrated that the pI values of SM deacylase, GlcCDase, SMase and ceramidase were 4.2, 7.4, 7.0 and 5.7, respectively. Those enzymic characteristics of SM-GCer deacylase are completely distinct from ceramidase as well as the other known deacylases. Our enzymic measurements demonstrated that SM-GCer deacylase activity is enhanced more than 5-fold in involved stratum corneum, more than 3-fold in uninvolved stratum corneum and approximately 3-fold in the involved epidermis from patients with AD compared with healthy controls. Our findings suggest that the novel enzyme, SM-GCer deacylase, is expressed in situ at significant levels in the epidermis of AD patients. This results in the production of SPC and GSP, instead of ceramides, which leads in turn to the ceramide deficiency seen in the stratum corneum of those patients. It is likely that the biogenesis of SM-GCer deacylase may be critical to the pathogenesis of AD.

PubMed Disclaimer

Similar articles

See all similar articles

Cited by

See all "Cited by" articles

MeSH terms

LinkOut - more resources