High impact information on STMN1

• Phosphoproteins of the stathmin family interact with the alphabeta tubulin heterodimer (tubulin) and hence interfere with microtubule dynamics [1].
• We propose that stathmin acts solely by sequestering tubulin, without affecting microtubule dynamics, and that the effect of stathmin phosphorylation on microtubule assembly depends on tubulin critical concentration [2].
• Stathmin is a highly conserved ubiquitous cytoplasmic protein, phosphorylated in response to extracellular signals and during the cell cycle [3].
• Stathmin slows down guanosine diphosphate dissociation from tubulin in a phosphorylation-controlled fashion [4].
• At molar ratios of stathmin to tubulin lower than 0.5, biphasic kinetics were observed, indicating that the dynamics of the complex is extremely slow, consistent with its high stability [4].

Biological context of STMN1

• The effect of stathmin phosphorylation on microtubule assembly depends on tubulin critical concentration [2].

Associations of STMN1 with chemical compounds

• The serine-to-glutamate substitution of all four phosphorylatable serines of stathmin (4E-stathmin) weakens the stability of the T(2)S complex by about 2 orders of magnitude [4].

Physical interactions of STMN1

• In this study we have used limited proteolysis and cross-linking analysis to localize further the stathmin-binding site on alpha-tubulin [5].

Analytical, diagnostic and therapeutic context of STMN1

• By immunofluorescence microscopy, we also found that stathmin binds to purified microtubules along their lengths in vitro [6].
• Finally, analysis of microtubule dynamics by video microscopy shows that, in our conditions, stathmin reduces the growth rate of microtubules with no effect on the catastrophe frequency [3].
• The stathmin/tubulin interaction leads to the formation of a 7.7 S complex with a 60-A Stokes radius, associating one stathmin with two tubulin heterodimer molecules as determined by direct quantification by Western blotting [3].

References