Metabolic control of oocyte apoptosis mediated by 14-3-3zeta-regulated dephosphorylation of caspase-2

Dev Cell. 2009 Jun;16(6):856-66. doi: 10.1016/j.devcel.2009.04.005.

Abstract

Xenopus oocyte death is partly controlled by the apoptotic initiator caspase-2 (C2). We reported previously that oocyte nutrient depletion activates C2 upstream of mitochondrial cytochrome c release. Conversely, nutrient-replete oocytes inhibit C2 via S135 phosphorylation catalyzed by calcium/calmodulin-dependent protein kinase II. We now show that C2 phosphorylated at S135 binds 14-3-3zeta, thus preventing C2 dephosphorylation. Moreover, we determined that S135 dephosphorylation is catalyzed by protein phosphatase-1 (PP1), which directly binds C2. Although C2 dephosphorylation is responsive to metabolism, neither PP1 activity nor binding is metabolically regulated. Rather, release of 14-3-3zeta from C2 is controlled by metabolism and allows for C2 dephosphorylation. Accordingly, a C2 mutant unable to bind 14-3-3zeta is highly susceptible to dephosphorylation. Although this mechanism was initially established in Xenopus, we now demonstrate similar control of murine C2 by phosphorylation and 14-3-3 binding in mouse eggs. These findings provide an unexpected evolutionary link between 14-3-3 and metabolism in oocyte death.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • 14-3-3 Proteins / metabolism*
  • Animals
  • Apoptosis*
  • Caspase 2 / metabolism*
  • Enzyme Activation
  • Female
  • Mice
  • Oocytes / cytology*
  • Oocytes / enzymology*
  • Phosphorylation
  • Protein Binding
  • Protein Phosphatase 1 / metabolism*
  • Xenopus

Substances

  • 14-3-3 Proteins
  • Protein Phosphatase 1
  • Caspase 2