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Structural & Functional Characterisation of Sds22
A Putative Mitotic Regulator of Protein Phosphatase-1

By Hugo Ceulemans
October 2001
Leuven University Press
ISBN: 9058671259
102 pages, illustrated
$46.50 paper original

Numerous cell processes are regulated via the dephosphorylation of key proteins by type-1 protein phosphatase (PP1) holoenzymes. In addition to the PP1 catalytic subunit, these holoenzymes contain one or more non-catalytic subunits that specify the localisation, activity and substrate affinity of the complex. This publication describes the characterisation of one such non-catalytic subunit, Sds22, which has been implicated in the regulation of mitosis. It reports on the genomic structure and the expression of the human and the mouse sds22-encoding gene and on the prediction of the three-dimensional structure of Sds22. Furthermore, it is discussed how determinants of Sds22 and of the catalytic subunit contribute to the interaction between the two proteins and to the functionality of Sds22.


  1. Introduction

    1. Reversible proetin phosphorylation
    2. The catalytic subunit of type-1 protein phosphatases
    3. Regulation and targeting of PP1 by non -catalytic subunits
    4. The Role of PPS in mitosis
  2. Aims and strategies
  3. Materials and methods
  4. Results and Discussion
    1. Structure and expression of human and murine PPPIR7
    2. The protein structure of Sds22
    3. The structure-function relationship of Sds22
    4. Exploration of the PP1 catalytic subunit as a ligand of Sds22
  5. General discussion and perspectives
  6. Summary/samenvatting
  7. References

Doctoral thesis.

Molecular Biology
Acta Biomedica Lovaniensia, No. 229