1 Department of Life Sciences, University of Siena, Siena, Italy.
2 Ministry of Education Key Laboratory of Protein Sciences, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China.
3 Department of Biology, Texas Agricultural and Mechanical University, College Station, TX, United States.
4 CRBM, Univ Montpellier, CNRS, Montpellier, France.