Human Cdc14B Promotes Progression through Mitosis by Dephosphorylating Cdc25 and Regulating Cdk1/Cyclin B Activity

Abstract

Entry into and progression through mitosis depends on phosphorylation and dephosphorylation of key substrates. In yeast, the nucleolar phosphatase Cdc14 is pivotal for exit from mitosis counteracting Cdk1-dependent phosphorylations. Whether hCdc14B, the human homolog of yeast Cdc14, plays a similar function in mitosis is not yet known. Here we show that hCdc14B serves a critical role in regulating progression through mitosis, which is distinct from hCdc14A. Unscheduled overexpression of hCdc14B delays activation of two master regulators of mitosis, Cdc25 and Cdk1, and slows down entry into mitosis. Depletion of hCdc14B by RNAi prevents timely inactivation of Cdk1/cyclin B and dephosphorylation of Cdc25, leading to severe mitotic defects, such as delay of metaphase/anaphase transition, lagging chromosomes, multipolar spindles and binucleation. The results demonstrate that hCdc14B-dependent modulation of Cdc25 phosphatase and Cdk1/cyclin B activity is tightly linked to correct chromosome segregation and bipolar spindle formation, processes that are required for proper progression through mitosis and maintenance of genomic stability.

Oncoprotein YAP Regulates the Spindle Checkpoint Activation in a Mitotic Phosphorylation-dependent Manner through Up-regulation of BubR1

“…1A). We tested the possibility that CDC14 phosphatase is involved in this process, because the CDC14 phosphatase controls mitotic exit by antagonizing/ dephosphorylating the CDK1-phosphorylated substrates in yeast (32) and in mammalian cells (33)(34)(35)(36)(37)(38)(39)(40). YAP migration in an SDS-PAGE gel was retarded (because of phosphorylation) following treatment with the spindle poison Taxol (23).…”

Human phosphatase CDC14A regulates actin organization through dephosphorylation of epithelial protein lost in neoplasm

“…One of the challenges for the identification of hCDC14A substrates is the transient nature of the interaction between the phosphatase and its substrate (27,28). The BioID approach is therefore highly attractive for this task as it is able to identify weakly interacting proteins because it supports efficient enrichment by virtue of the fact that neighbors are identified as a result of their biotinylation by hyperactive promiscuous biotin ligase BirA that has been fused to the protein of interest (22).…”

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 …”

“…Cdk1-cyclin B phosphorylates human Cdc25A S18, S40, S88, S116, S261 and S283 in vitro. [149] Of these sites, human Cdc14A dephosphorylates S116, Cdc14B targets S88 and S261, while both phosphatases can dephosphorylate S40. Cdc14A was independently identified as also dephosphorylating Cdc25A S321.…”

“…[151] siRNA knockdown of Cdc14B leads to accumulation of phosphorylated Cdc25B and Cdc25C. [149] In S. pombe Cdc14 homologue Clp1 dephosphorylates Cdc25 and this is required for its ubiquitination and APC mediated proteolysis at the end of mitosis. [73] Similarly, in vertebrates Cdc25A and Cdc25B are targeted by the APC at mitotic exit.…”