TY - JOUR
T1 - Structural basis of protein condensation on microtubules underlying branching microtubule nucleation
AU - Guo, Changmiao
AU - Alfaro-Aco, Raymundo
AU - Zhang, Chunting
AU - Russell, Ryan W.
AU - Petry, Sabine
AU - Polenova, Tatyana
N1 - Funding Information:
We thank Dr. Istvan Pelczer for assistance in data acquisition on the 800 MHz NMR spectrometer at Princeton University. This work was partially supported by an NIH New Innovator Award 1DP2GM123493, the Pew Scholars Program in the Biomedical Sciences (00027340), and the David and Lucile Packard Foundation 2014–40376 (all to S.P.). We acknowledge the support of the National Science Foundation (NSF grant CHE-0959496) for the acquisition of the 850 MHz NMR spectrometer and of the National Institutes of Health (NIH Grant P30GM110758) for the support of core instrumentation infrastructure at the University of Delaware.
Funding Information:
We thank Dr. Istvan Pelczer for assistance in data acquisition on the 800 MHz NMR spectrometer at Princeton University. This work was partially supported by an NIH New Innovator Award 1DP2GM123493, the Pew Scholars Program in the Biomedical Sciences (00027340), and the David and Lucile Packard Foundation 2014–40376 (all to S.P.). We acknowledge the support of the National Science Foundation (NSF grant CHE-0959496) for the acquisition of the 850 MHz NMR spectrometer and of the National Institutes of Health (NIH Grant P30GM110758) for the support of core instrumentation infrastructure at the University of Delaware.
Publisher Copyright:
© 2023, The Author(s).
PY - 2023/12
Y1 - 2023/12
N2 - Targeting protein for Xklp2 (TPX2) is a key factor that stimulates branching microtubule nucleation during cell division. Upon binding to microtubules (MTs), TPX2 forms condensates via liquid-liquid phase separation, which facilitates recruitment of microtubule nucleation factors and tubulin. We report the structure of the TPX2 C-terminal minimal active domain (TPX2α5-α7) on the microtubule lattice determined by magic-angle-spinning NMR. We demonstrate that TPX2α5-α7 forms a co-condensate with soluble tubulin on microtubules and binds to MTs between two adjacent protofilaments and at the intersection of four tubulin heterodimers. These interactions stabilize the microtubules and promote the recruitment of tubulin. Our results reveal that TPX2α5-α7 is disordered in solution and adopts a folded structure on MTs, indicating that TPX2α5-α7 undergoes structural changes from unfolded to folded states upon binding to microtubules. The aromatic residues form dense interactions in the core, which stabilize folding of TPX2α5-α7 on microtubules. This work informs on how the phase-separated TPX2α5-α7 behaves on microtubules and represents an atomic-level structural characterization of a protein that is involved in a condensate on cytoskeletal filaments.
AB - Targeting protein for Xklp2 (TPX2) is a key factor that stimulates branching microtubule nucleation during cell division. Upon binding to microtubules (MTs), TPX2 forms condensates via liquid-liquid phase separation, which facilitates recruitment of microtubule nucleation factors and tubulin. We report the structure of the TPX2 C-terminal minimal active domain (TPX2α5-α7) on the microtubule lattice determined by magic-angle-spinning NMR. We demonstrate that TPX2α5-α7 forms a co-condensate with soluble tubulin on microtubules and binds to MTs between two adjacent protofilaments and at the intersection of four tubulin heterodimers. These interactions stabilize the microtubules and promote the recruitment of tubulin. Our results reveal that TPX2α5-α7 is disordered in solution and adopts a folded structure on MTs, indicating that TPX2α5-α7 undergoes structural changes from unfolded to folded states upon binding to microtubules. The aromatic residues form dense interactions in the core, which stabilize folding of TPX2α5-α7 on microtubules. This work informs on how the phase-separated TPX2α5-α7 behaves on microtubules and represents an atomic-level structural characterization of a protein that is involved in a condensate on cytoskeletal filaments.
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U2 - 10.1038/s41467-023-39176-z
DO - 10.1038/s41467-023-39176-z
M3 - Article
C2 - 37344496
AN - SCOPUS:85163109661
SN - 2041-1723
VL - 14
JO - Nature communications
JF - Nature communications
IS - 1
M1 - 3682
ER -