Cyclin D1 Stability Is Partly Controlled by O-GlcNAcylation

Abstract

Cyclin D1 is the regulatory partner of the cyclin-dependent kinases (CDKs) CDK4 or CDK6. Once associated and activated, the cyclin D1/CDK complexes drive the cell cycle entry and G1 phase progression in response to extracellular signals. To ensure their timely and accurate activation during cell cycle progression, cyclin D1 turnover is finely controlled by phosphorylation and ubiquitination. Here we show that the dynamic and reversible O- linked β-N-Acetyl-glucosaminylation ( O -GlcNAcylation) regulates also cyclin D1 half-life. High O -GlcNAc levels increase the stability of cyclin D1, while reduction of O -GlcNAcylation strongly decreases it. Moreover, elevation of O -GlcNAc levels through O -GlcNAcase (OGA) inhibition significantly slows down the ubiquitination of cyclin D1. Finally, biochemical and cell imaging experiments in human cancer cells reveal that the O -GlcNAc transferase (OGT) binds to and glycosylates cyclin D1. We conclude that O -GlcNAcylation promotes the stability of cyclin D1 through modulating its ubiquitination.

Inhibitory effect of dihydromyricetin on the proliferation of JAR cells and its mechanism of action

“…Cyclin D was first isolated in a study on parathyroid carcinoma conducted by Motokura et al (20), and it is necessary in the G 1 /S phase of the cell cycle. Cyclin D is generally considered to play a regulatory role by combining with cycle-dependent kinases (CDKs; CDK4 or CDK6) to promote transition from the G 1 to the S phase (21). The overexpression of cyclin D1 and CDK4 can cause abnormal proliferation and uncontrolled Figure 4.…”

Metabolic sensor O-GlcNAcylation regulates megakaryopoiesis and thrombopoiesis through c-Myc stabilization and integrin perturbation

“…19,42 Our data indicate that O-GlcNAcylation regulates c-Myc stability in MBs/MKs, which is mediated through ubiquitin-mediated proteasomal degradation, consistent with previous reports in lung carcinoma. 20,43 The counteraction of O-GlcNAcylation and ubiquitination has been increasingly reported, namely in circadian rhythm proteins BMAL1 and CLOCK, 44 apoptotic protein tBid 45 and cell cycle regulator cyclin D1, 46 although an enhanced ubiquitination upon increasing of O-GlcNAcylation was also observed in the other reports. 20,47 We additionally found that F I G U R E 7 Inhibition of OGT and c-Myc affects cell adhesion network.…”

OGT Controls the Expression and the Glycosylation of E‐cadherin, and Affects Glycosphingolipid Structures in Human Colon Cell Lines

“…SiRNA‐transfected cells were lysed in lysis buffer (50 m m Tris pH 7.5, 150 m m NaCl, 1% NP‐40, 0.25% sodium deoxycholate and 0.1% SDS, and protease inhibitors). Immunoprecipitation and Western blotting were performed as previously described, except for the detection of Sd a antigen which was revealed with a specific antibody as described by Groux et al . Lectin blotting was performed as described in the supplemental file.…”

“…Cells were transfected with siRNA (si Control, siOGT) and grown in 6‐well plates on glass coverslips for 3 days. Cells were fixed as previously described and directly incubated with E‐cadherin primary antibody and lectin, followed by incubation with secondary antibody and DyLight 488 Streptavidin . Images were acquired using an inverted Zeiss LSM700 confocal microscope with a 40x oil immersion lens and data were collected with the ZEN 2010 software (Zeiss).…”