The Cdk/Cdc14 Module Controls Activation of the Yen1 Holliday Junction Resolvase to Promote Genome Stability

Abstract

SUMMARY Faithful genome transmission during cell division requires precise, coordinated action of DNA metabolic enzymes, including proteins responsible for DNA damage detection and repair. Dynamic phosphorylation plays an important role in controlling repair enzymes during the DNA damage response (DDR). Cdc14 phosphatases oppose cyclin-dependent kinase (Cdk) phosphorylation and have been implicated in the DDR in several model systems. Using new insight into Cdc14 specificity we identified the budding yeast Holliday junction resolvase Yen1 as the first DNA repair target of Cdc14. Cdc14 activation at anaphase triggers nuclear accumulation and enzymatic activation of Yen1, likely to resolve persistent recombinational repair intermediates. Consistent with this, expression of a phosphomimetic Yen1 mutant increased sister chromatid non-disjunction. In contrast, lack of Cdk phosphorylation resulted in constitutive activity and elevated crossover-associated repair. The precise timing of Yen1 activation, governed by core cell cycle regulators, helps coordinate DNA repair with chromosome segregation and safeguards against genome destabilization.

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

“…1C). This analysis is consistent with structural data (26) indicating that hCDC14A shares a common preference with cyclin-dependent kinases in being proline directed with a preference for lysine or arginine three residues after the phosphorylation site (25). The presence of proline residues at positions -1, -2, and +2 indicates that hCDC14A may also counteract other kinases such as ERK1/2 and glycogen synthase kinase 3 (GSK-3β) that emulate cyclin-dependent kinases in being proline-directed kinases yet have a preference for additional proline residues surrounding the phosphorylation site (www.phosphosite.org/).…”

“…Of the 68 hypo-phosphorylated peptides, 65 (95.6%) contained phosphoserine (P-serine) residues and only 3 (4.4%) phospho-threonine (P-threonine), whereas P-serine represented 80.6% and P-threonine 18.6% of the global phospho-proteome of these cells. Thus, in line with in vitro data, in vivo hCDC14A also appears to preferentially target P-serine residues (24,25).…”

Resolvase OsGEN1 Mediates DNA Repair by Homologous Recombination

“…The activities of yeast Yen1 and human GEN1 are controlled by master cell cycle regulators and are regulated by phosphorylation or dephosphorylation. The phosphorylation sites reside in the C terminus of Yen1/GEN1 (Blanco et al, 2014;Chan and West, 2014;Eissler et al, 2014). We hypothesize that the function of OsGEN1 may be controlled by regulators through interaction with its C terminus.…”

Resolution of single and double Holliday junction recombination intermediates by GEN1

“…In yeast, Yen1 exhibits low activity in S phase, because cyclindependent kinase (Cdk) promotes its phosphorylation, leading to nuclear exclusion and inhibition of catalytic activity by reducing its affinity for DNA (34,35). Then, later in the cell cycle, Yen1 is dephosphorylated by Cdc14; dephosphorylation promotes nuclear localization and DNA binding, leading to enzymatic activation (36)(37)(38). GEN1 is also regulated, but in this case by a mechanism that seems to be independent of phosphorylation, because its activity is controlled primarily by nuclear exclusion (39).…”