The Binding Mode of a Tau Peptide with Tubulin

Abstract

The microtubule-associated protein Tau promotes the polymerization of tubulin and modulates the function of microtubules. As a consequence of the dynamic nature of the Tau-tubulin interaction, the structural basis of this complex has remained largely elusive. By using NMR methods optimized for ligand-receptor interactions in combination with site-directed mutagenesis we demonstrate that the flanking domain downstream of the four microtubule-binding repeats of Tau binds competitively to a site on the α-tubulin surface. The binding process is complex, involves partial coupling of different interacting regions, and is modulated by phosphorylation at Y394 and S396. This study strengthens the hypothesis of an intimate relationship between Tau phosphorylation and tubulin binding and highlights the power of the INPHARMA NMR method to characterize the interaction of peptides derived from intrinsically disordered proteins with their molecular partners.

Targeted Polypeptide–Microtubule Aggregation with Cucurbit[8]uril for Enhanced Cell Apoptosis

“…Thec onstruction of the (BP&CB [8])@MT supramolecular assembly is depicted in Figure 1. Thesynthetic route and compound characterization of the guest peptide BP are shown in the Supporting Information (Supporting Information, Figures S1-S10).…”

“…[3] Thep olymerization and depolymerization of MTs have critical relevance to cell division and intracellular transport, which make these inter-networked tubular arrays attractive molecular targets for cancer chemotherapy [4] and biomolecular assemblies. [7,8] Thed esign of our system was based on the inspection of aselected polypeptide containing ten amino acids,which was identified by computational analysis and exhibited antimitotic activity by competitive binding with the a-tubulin subunit. [7,8] Thed esign of our system was based on the inspection of aselected polypeptide containing ten amino acids,which was identified by computational analysis and exhibited antimitotic activity by competitive binding with the a-tubulin subunit.…”

“…[7,8] Thed esign of our system was based on the inspection of aselected polypeptide containing ten amino acids,which was identified by computational analysis and exhibited antimitotic activity by competitive binding with the a-tubulin subunit. In our case,t he chemical modification of ab enzylimidazolium moiety with an antimitotic polypeptide (BP) did not interfere with its original tubulin-targeting ability,b ut it provided af unctional anchoring point to noncovalently interact with cucurbiturils (CB [7] and CB [8]). In our case,t he chemical modification of ab enzylimidazolium moiety with an antimitotic polypeptide (BP) did not interfere with its original tubulin-targeting ability,b ut it provided af unctional anchoring point to noncovalently interact with cucurbiturils (CB [7] and CB [8]).…”

“…[9] To further explore the curative effect of supramolecular intertubular aggregation, we present an entirely self-assembled microtubular system, which is fabricated by the combination of primary tubulin-tubulin heterodimerization, specific peptide-tubulin recognition, and cooperative host-guest complexation. Moreover,t he 2:1h omoternary BP&CB [8] complexation with MTs could exclusively induce the dramatic morphological change of MTs from linear polymers to spherical nanostructures.S ignificantly,ahighly efficacious anticancer potencyw as achieved after treatment with BP&CB [8] complex, as evidenced by more compact MTs in the cellular environment and higher levels of apoptosis in the tumor tissues.T hus,i ta ppears that the enhanced intertubular aggregation arising from the precise and orthogonal supramolecular motifs can be exploited as an ovel strategy in the battle against MT-aggregation-related diseases. Moreover,t he 2:1h omoternary BP&CB [8] complexation with MTs could exclusively induce the dramatic morphological change of MTs from linear polymers to spherical nanostructures.S ignificantly,ahighly efficacious anticancer potencyw as achieved after treatment with BP&CB [8] complex, as evidenced by more compact MTs in the cellular environment and higher levels of apoptosis in the tumor tissues.T hus,i ta ppears that the enhanced intertubular aggregation arising from the precise and orthogonal supramolecular motifs can be exploited as an ovel strategy in the battle against MT-aggregation-related diseases.…”

“…Theh ost-guest binding behaviors were preliminarily explored by 1 HNMR spectroscopy.A sd iscerned from Figure 2, the proton signals of benzyl (H a-d )and imidazolium (H e )g roups in the guest peptide BP exhibited pronounced upfield shifts,while the proton signal of the methylene group in the acylmethylene linker (H f )s hifted downfield upon complexation with CB [7] and CB [8].I nc ontrast, the resonance signals of the polypeptide chain were almost unchanged upon addition of CB [7] and CB [8] (dashed box in Figure 2). These complexation-induced chemical-shift changes were further elucidated using the carboxylated precursor (BA, Figure 1) as ar eference compound.…”