Short 42 C heat shock induces phosphorylation and degradation of Cdc25A which depends on p38MAPK, Chk2 and 14.3.3

Abstract

The effects of heat shock (HS; 42 degrees C) on the cell cycle and underlying molecular mechanisms are astonishingly unexplored. Here, we show that HS caused rapid Cdc25A degradation and a reduction of cell cycle progression. Cdc25A degradation depended on Ser75-Cdc25A phosphorylation caused by p38MAPK and Chk2, which phosphorylated Ser177-Cdc25A that is specific for 14.3.3 binding. Upon HS, Cdc25A rapidly co-localized with 14.3.3 in the perinuclear space that was accompanied with a decrease of nuclear Cdc25A protein levels. Consistently, a 14.3.3 binding-deficient Cdc25A double mutant (Ser177/Ala-Tyr507/Ala) was not degraded in response to HS and there was no evidence for an increased co-localization of Cdc25A with 14.3.3 in the cytosol. Therefore, upon HS, p38, Chk2 and 14.3.3 were antagonists of Cdc25A stability. On the other hand, Cdc25A was protected by Hsp90 in HEK293 cells because the specific inhibition of Hsp90 with Geldanamycin caused Cdc25A degradation in HEK293 implicating that Cdc25A is an Hsp90 client. Specific inhibition of Hsp90 together with HS caused and accelerated degradation of Cdc25A and was highly cytotoxic. The results presented here show for the first time that Cdc25A is degraded by moderate heat shock and protected by Hsp90. We describe the mechanisms explaining HS-induced cell cycle retardation and provide a rationale for a targeted hyperthermia cancer therapy.

An apolar extract of Critonia morifolia inhibits c-Myc, cyclin D1, Cdc25A, Cdc25B, Cdc25C and Akt and induces apoptosis

“…In S-phase, cells were arrested a second time, because meanwhile Cdc25B became degraded and Chk2 strongly activated (39). The activity of Chk1 and Chk2 was reflected by the increased phosphorylation levels of Ser75 and Ser177 of Cdc25A, respectively (23,40). The temporally separated effects on cell cycle inhibition were probably due to distinct anti-neoplastic compounds present in the petroleum ether extract.…”

DNA Damage Induced by Ultrasound and Cellular Responses

“…Accumulating evidence has shown that HS can cause G 1 and G 2 /M arrest [54][55][56] p53-dependent transcription of p21 and p38 MAPK dependent CDC25A degradation were demonstrated as mechanisms for HS-induced G 1 arrest [57]. However, the molecular mechanism underlying G 2 /M checkpoint activation in cells exposed to HS had not been extensively investigated.…”

Phosphorylation Mediated Regulation of Cdc25 Activity, Localization and Stability

“…S99, S148, S178, S192, S204, S206, T226, S234, S359, T561, S567, T569 [60,156,157,162] Cdk1-cyclin B S18, S40, S88, S116, S261, S283, S321 [149,151,167] Chk1 S76, S124, S178, T507 [168][169][170][171][172][173]200] Chk2 S124, S278 [173,175] Casein Kinase 1ε S82 [199] Casein Kinase 1α S79, S82 [198] p38 S76, S124 [168,175] GSK-3β S76 [193,194] NEK11 S82, S88 [187] Plk3 S80 [193,194] Cdk1-cyclinB S50, S160, S321 [135,136,246] Chk1 S151, S230, S323, S563 [236,238,239] Aurora S353 [124] Casein Kinase 2 S186, S187 [235] JNK S101, S103 [280] MEK/ERK S249 [259] p38 S323 [208] MK2 S323 [210] Plk1 T167, S209, T404, S465 [136] Cdk1/cyclin B T48, T67, S122, T130, S168, S214 [42,143,145,246] Chk1 S216, S247, S263 [219-221, 225, 226] Chk2 S216 [209,242] Casein Kinase 2 T236 …”

“…[168,169,[174][175][176] In the original cloning of human Cdc25A. [37], there are several substitutions in the N-terminus (Accession: AAA58415.1) and a one residue gap corresponding to residue R12 in all other full length human Cdc25A sequences in the NCBI database (Accession: P30304).…”

“…p38 also phosphorylates human Cdc25A on S124 and S76 in response to osmotic stress, destabilizing the protein [168] and a 42 C heatshock causes p38 and Chk2 to phosphorylate S76 and S178 of human Cdc25A, respectively. [175] MAPKAP kinase 2 (MK2) functions downstream of p38 and regulates G1 and S-phase cell cycle progression in response to UV. [210] Downstream of p38, it phosphorylates RxxS/T motifs and activation of MK2…”