A synergistic relationship between three regions of stathmin family proteins is required for the formation of a stable complex with tubulin.
Stathmin is a ubiquitous 17 kDa cytosolic phosphoprotein proposed to play a general role in the integration and relay of intracellular signalling pathways. It is believed to regulate microtubule dynamics by sequestering tubulin in a complex made of two tubulin heterodimers per stathmin molecule (T2S complex). The other proteins of the stathmin family can also bind two tubulin heterodimers through their SLD (stathmin-like domain), but the different tubulin:SLD complexes display varying stabilities. In this study, we analysed the relative influence of three regions of SLDs on the interaction with tubulin and the mechanistic processes that lead to its sequestration. Tubulin-binding properties of fragments and chimaeras of stathmin and RB3(SLD) were studied in vitro by tubulin polymerization, size-exclusion chromatography and surface plasmon resonance assays. Our results show that the N-terminal region of SLDs favours the binding of the first tubulin heterodimer and that the second C-terminal tubulinbinding site confers the specific stability of a given tubulin:SLD complex. Our results highlight the molecular processes by which tubulin co-operatively interacts with the SLDs. This knowledge may contribute to drug development aimed at disturbing microtubules that could be used for the treatment of cancer.
Jourdain
Isabelle
I
Signalisation et Différenciation Cellulaires dans les Systèmes Nerveux et Musculaire, U440 Institut National de la Santé et de la Recherche Médicale/Université Pierre et Marie Curie, Paris, France.
Lachkar
Sylvie
S
Charbaut
Elodie
E
Gigant
Benoit
B
Knossow
Marcel
M
Sobel
André
A
Curmi
Patrick A
PA
D000595:Amino Acid Sequence; D001665:Binding Sites; D046911:Macromolecular Substances; D008744:Methylamines / Q000494:pharmacology; D008868:Microtubule Proteins; D008969:Molecular Sequence Data; D009414:Nerve Growth Factors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D010750:Phosphoproteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000378:metabolism; D050777:Stathmin; D014404:Tubulin / Q000378:metabolism*
D046911:Macromolecular Substances; D008744:Methylamines; D008868:Microtubule Proteins; D009414:Nerve Growth Factors; D010750:Phosphoproteins; D011993:Recombinant Fusion Proteins; C491795:STMN4 protein, human; D050777:Stathmin; D014404:Tubulin; C005855:trimethyloxamine