Student or educator? Sign up with your school email and get 6 months of Pro free.
Cited by 300

The DOI matches its Crossref record; 34 of the 34 references it cites were found in a registry or an index.

Long Chain Ceramides Activate Protein Phosphatase-1 and Protein Phosphatase-2A

Open access
Chalfant, Charles E., Kishikawa, Katsuya, Mumby, Marc C., Kamibayashi, Craig, Bielawska, Alicja, Hannun, Yusuf A.·1999·Journal of Biological Chemistry

Abstract

The search for potential targets for ceramide action led to the identification of ceramide-activated protein phosphatases, which include protein phosphatase-2A (PP2A) and protein phosphatase-1 (PP1) with roles in regulating apoptosis and cell growth. Thus far, in vitro studies on ceramide-activated protein phosphatases have been restricted to the use of short chain ceramides, limiting the extent of mechanistic insight. In this study, we show that the long chain D-erythro-C18-ceramide activated PP2A (AB'C trimer), PP2Ac (catalytic subunit of PP2A), and PP1gammac and -alphac (catalytic subunits of PP1gamma and -1alpha isoforms, respectively) 2-6-fold in the presence of dodecane, a lipid-solubilizing agent, with 50% maximal activation achieved at approximately 10 microM D-erythro-C18-ceramide. The diastereoisomers of D-erythroC18-ceramide, D-threo-, and L-threo-C18-ceramide, as well as the enantiomeric L-erythro-C18-ceramide, did not activate PP1 or PP2A, but they inhibited PP1 and PP2A activity. The addition of phosphatidic acid decreased the basal activity of PP1c but also increased the stimulation by D-erythro-C18-ceramide from 1.8- to 2. 8-fold and decreased the EC50 of D-erythro-C18-ceramide to 4.45 microM. The addition of 150 mM KCl decreased the basal activity of PP1 and the dose of D-erythro-C18-ceramide necessary to activate PP1c (EC50 = 6.25 microM) and increased the ceramide responsiveness up to 10-17-fold. These studies disclose stereospecific activation of PP1 and PP2A by long chain natural ceramides under near physiologic ionic strengths in vitro. The implications of these studies for mechanisms of ceramide action are discussed.

Overview

The claims and statistics of this paper haven’t been checked yet.

Run the check — free, no account needed. It reads the open-access text and checks the sources it cites.

A few free checks a day · papers already verified open instantly · results are public

Integrity signals

Registry

Crossref · 10.1074/jbc.274.29.20313

Cites

34 of 34 references verified0 citation errors · 0 not checkable

Statistics

Verification

Claims the paper makes

The claims and statistics of this paper haven’t been checked yet.

Run the check — free, no account needed. It reads the open-access text and checks the sources it cites.

A few free checks a day · papers already verified open instantly · results are public

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

The self-check needs the paper’s full text.

Citations

Cites

Show all 34 references

Cited by

See all 300

Metadata

Authors
Chalfant, C. E., Kishikawa, K., Mumby, M. C., Kamibayashi, C., Bielawska, A., & Hannun, Y. A.
Venue
Journal of Biological Chemistry
Publisher
Elsevier BV
Published
1999-07
Volume
274
Issue
29
Pages
20313-20317
ISSN
0021-9258 (ISSN-L)
OpenAlex
W2079828650
Cited by
300
References
34
FWCI
5.22
Type
journal article
Language
en
Open access
hybrid

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

What counts as a claim ›How we measure confidence ›How we check this ›

Are you an author, or do you see a problem with this page? Request a review

How to cite

Cite CoChat for the checks on this page, and the paper for its own findings.

This page
CoChat. (2026). Citation check: Long Chain Ceramides Activate Protein Phosphatase-1 and Protein Phosphatase-2A. https://app.cochat.ai/papers/10.1074/jbc.274.29.20313
The paper
Chalfant, C. E., Kishikawa, K., Mumby, M. C., Kamibayashi, C., Bielawska, A., & Hannun, Y. A. (1999). Long Chain Ceramides Activate Protein Phosphatase-1 and Protein Phosphatase-2A. Journal of Biological Chemistry. https://doi.org/10.1074/jbc.274.29.20313

Data sources

Bibliographic data: Semantic Scholar, OpenAlex, Crossref.

Contains information from the Semantic Scholar Academic Graph Datasets, made available under the ODC Attribution License (ODC-BY 1.0).

Semantic Scholar’s data is described in: Kinney, R., et al. (2023). The Semantic Scholar Open Data Platform. arXiv:2301.10140.