[1] Max Planck Inst Biol Ageing MPI AGE, D-50931 Cologne, Germany
[2] Univ Cologne, Cologne Excellence Cluster Cellular Stress Respon, D-50931 Cologne, Germany
[3] Univ Cologne, Fac Med, D-50931 Cologne, Germany
[4] Univ Hosp Cologne, Ctr Biochem, D-50931 Cologne, Germany