scholarly journals Regulation of tau’s proline rich region by its N-terminal domain

2019 ◽  
Author(s):  
Kristen McKibben ◽  
Elizabeth Rhoades
Keyword(s):  
Binding Domain ◽  
Rich Region ◽  
Tau Function ◽  
Microtubule Binding ◽  
Intrinsically Disordered ◽  
Terminal Domain ◽  
Microtubule Polymerization ◽  
Tubulin Binding ◽  
Proline Rich Region

AbstractTau is an intrinsically disordered, microtubule-associated protein with a role in regulating microtubule dynamics. Despite intensive research, the molecular mechanisms of taumediated microtubule polymerization are poorly understood. Here we use single molecule fluorescence to investigate the role of tau’s N-terminal domain (NTD) and proline rich region (PRR) in regulating interactions of tau with soluble tubulin. Both full-length tau isoforms and truncated variants are assayed for their ability to bind soluble tubulin and stimulate microtubule polymerization. We describe a novel role for tau’s PRR as an independent tubulin-binding domain with polymerization capacity. In contrast to the relatively weak tubulin interactions distributed throughout the microtubule binding repeats (MTBR), resulting in heterogeneous tau:tubulin complexes, the PRR binds tubulin tightly and stoichiometrically. Moreover, we demonstrate that interactions between the PRR and MTBR are reduced by the NTD through a conserved conformational ensemble. Based on our data, we propose that tau’s PRR can serve as a core tubulin-binding domain, while the MTBR enhances polymerization capacity by increasing the local tubulin concentration. The NTD negatively regulates tubulin-binding interactions of both of these domains. This study draws attention to the central role of the PRR in tau function, as well as providing mechanistic insight into tau-mediated polymerization of tubulin.Significance StatementTau is an intrinsically disordered, microtubule associated protein linked to a number of neurodegenerative disorders. Here we identify tau’s proline rich region as having autonomous tubulin binding and polymerization capacity, which is enhanced by the flanking microtubule binding repeats. Moreover, we demonstrate that tau’s N-terminal domain negatively regulates both binding and polymerization. We propose a novel model for tau-mediated polymerization whereby the proline rich region serves as a core tubulin-binding domain, while the microtubule binding repeats increase the local concentration. Our work draws attention to the importance of the proline rich region and N-terminal domain in tau function, and highlights the proline rich region as a putative target for the development of therapeutics.

scholarly journals Structure and Functional Role of Dynein's Microtubule-Binding Domain

Science ◽  
2008 ◽  
Vol 322 (5908) ◽  
pp. 1691-1695 ◽  
Author(s):  
A. P. Carter ◽  
J. E. Garbarino ◽  
E. M. Wilson-Kubalek ◽  
W. E. Shipley ◽  
C. Cho ◽  
...  
Keyword(s):  
Functional Role ◽  
Binding Domain ◽  
Microtubule Binding ◽  
Microtubule Binding Domain

scholarly journals Autoregulatory control of microtubule binding in doublecortin-like kinase 1

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Regina L Agulto ◽  
Melissa M Rogers ◽  
Tracy C Tan ◽  
Amrita Ramkumar ◽  
Ashlyn M Downing ◽  
...  
Keyword(s):  
Binding Affinity ◽  
Therapeutic Target ◽  
Kinase Activity ◽  
Kinase Inhibitors ◽  
Binding Domain ◽  
Cancer Development ◽  
Microtubule Binding ◽  
Microtubule Binding Domain

The microtubule-associated protein, doublecortin-like kinase 1 (DCLK1), is highly expressed in a range of cancers and is a prominent therapeutic target for kinase inhibitors. The physiological roles of DCLK1 kinase activity and how it is regulated remain elusive. Here, we analyze the role of mammalian DCLK1 kinase activity in regulating microtubule binding. We find that DCLK1 autophosphorylates a residue within its C-terminal tail to restrict its kinase activity and prevent aberrant hyperphosphorylation within its microtubule-binding domain. Removal of the C-terminal tail or mutation of this residue causes an increase in phosphorylation within the doublecortin domains, which abolishes microtubule binding. Therefore, autophosphorylation at specific sites within DCLK1 have diametric effects on the molecule's association with microtubules. Our results suggest a mechanism by which DCLK1 modulates its kinase activity to tune its microtubule-binding affinity. These results provide molecular insights for future therapeutic efforts related to DCLK1's role in cancer development and progression.

The projection domain of MAP2b regulates microtubule protrusion and process formation in Sf9 cells

2002 ◽  
Vol 115 (7) ◽  
pp. 1523-1539 ◽  
Author(s):  
Dave Bélanger ◽  
Carole Abi Farah ◽  
Minh Dang Nguyen ◽  
Michel Lauzon ◽  
Sylvie Cornibert ◽  
...  
Keyword(s):  
Cell Surface ◽  
Binding Domain ◽  
Intramolecular Interactions ◽  
Microtubule Assembly ◽  
Sf9 Cells ◽  
Microtubule Binding ◽  
Process Formation ◽  
Microtubule Binding Domain ◽  
Projection Domain

The expression of microtubule-associated protein 2 (MAP2), developmentally regulated by alternative splicing, coincides with neurite outgrowth. MAP2 proteins contain a microtubule-binding domain (C-terminal) that promotes microtubule assembly and a poorly characterized domain, the projection domain(N-terminal), extending at the surface of microtubules. MAP2b differs from MAP2c by an additional sequence of 1372 amino acids in the projection domain. In this study, we examined the role of the projection domain in the protrusion of microtubules from the cell surface and the subsequent process formation in Sf9 cells. In this system, MAP2b has a lower capacity to induce process formation than MAP2c. To investigate the role of the projection domain in this event, we expressed truncated forms of MAP2b and MAP2c that have partial or complete deletion of their projection domain in Sf9 cells. Our results indicate that process formation is induced by the microtubule-binding domain of these MAP2 proteins and is regulated by their projection domain. Furthermore, the microtubule-binding activity of MAP2b and MAP2c truncated forms as well as the structural properties of the microtubule bundles induced by them do not seem to be the only determinants that control the protrusion of microtubules from the cell surface in Sf9 cells. Rather, our data suggest that microtubule protrusion and process formation are regulated by intramolecular interactions between the projection domain and its microtubule-binding domain in MAP2b.

Possible Role of Each Repeat Structure of the Microtubule-Binding Domain of the Tau Protein in In Vitro Aggregation

2005 ◽  
Vol 138 (4) ◽  
pp. 413-423 ◽  
Author(s):  
Koji Tomoo ◽  
Tian-Ming Yao ◽  
Katsuhiko Minoura ◽  
Shuko Hiraoka ◽  
Miho Sumida ◽  
...  
Keyword(s):  
Tau Protein ◽  
Binding Domain ◽  
Microtubule Binding ◽  
Repeat Structure ◽  
Microtubule Binding Domain

scholarly journals Second-Site Changes Affect Viability of Amphotropic/Ecotropic Chimeric Enveloped Murine Leukemia Viruses

2000 ◽  
Vol 74 (2) ◽  
pp. 899-913 ◽  
Author(s):  
Lucille O'Reilly ◽  
Monica J. Roth
Keyword(s):  
Receptor Binding ◽  
Single Point ◽  
Cell Types ◽  
Binding Domain ◽  
Receptor Binding Domain ◽  
Rich Region ◽  
C Terminus ◽  
Nih 3T3 ◽  
Proline Rich Region ◽  
Murine Leukemia

ABSTRACT Chimeras were previously generated between the ecotropic (Moloney-MuLV) and amphotropic (4070A) SU and TM proteins of murine leukemia virus (MuLV). After passage in D17 cells, three chimeras with junctions in the C terminus of SU (AE5, AE6, and AE7), showed improved kinetics of viral spreading, suggesting that they had adapted. Sequencing of the viruses derived from the D17 cell lines revealed second-site changes within the env gene. Changes were detected in the receptor binding domain, the proline-rich region, the C terminus of SU, and the ectodomain of TM. Second-site changes were subcloned into the parental DNA, singly and in combination, and tested for viability. All viruses had maintained their original cloned mutations and junctions. Reconstruction and passage of AE7 or AE6 virus with single point mutations recovered the additional second-site changes identified in the parental population. The AE5 isolate required changes in the VRA, the VRC, the VRB-hinge region, and the C terminus of SU for efficient infection. Passage of virus, including the parental 4070A, in D17 cells resulted in a predominant G100R mutation within the receptor binding domain. Viruses were subjected to titer determination in three cell types, NIH 3T3, canine D17, and 293T. AE6 viruses with changes in the proline-rich region initially adapted for growth on D17 cells could infect all cell types tested. AE6-based chimeras with additional mutations in the C terminus of SU could infect D17 and 293T cells. Infection of NIH 3T3 cells was dependent on the proline-rich mutation. AE7-based chimeras encoding L538Q and G100R were impaired in infecting NIH 3T3 and 293T cells.

scholarly journals Polyphosphate initiates tau aggregation through intra- and intermolecular scaffolding

2019 ◽  
Author(s):  
S. P. Wickramasinghe ◽  
J. Lempart ◽  
H. E. Merens ◽  
J. Murphy ◽  
U. Jakob ◽  
...  
Keyword(s):  
Conformational Changes ◽  
Binding Sites ◽  
Cross Linking ◽  
Conformational Ensemble ◽  
Intensive Study ◽  
Rich Region ◽  
Microtubule Binding ◽  
Long Range Interactions ◽  
Tau Aggregation ◽  
Proline Rich Region

AbstractThe aggregation and deposition of tau is a hallmark of a class of neurodegenerative diseases called tauopathies. Despite intensive study, cellular and molecular factors that trigger tau aggregation are not well understood. Here we provide evidence for two mechanisms relevant to the initiation of tau aggregation in the presence of cytoplasmic polyphosphates (polyP): changes in the conformational ensemble of monomer tau and noncovalent cross-linking of multiple tau monomers. We identified conformational changes throughout full-length tau, most notably diminishment of long-range interactions between the termini coupled with compaction of the microtubule binding and proline rich regions. We found that while the proline rich and microtubule binding regions both contain polyP binding sites, the proline rich region is a requisite for compaction of the microtubule binding region upon binding. Additionally, both the magnitude of the conformational change and the aggregation of tau are dependent on the chain length of the polyP polymer. Longer polyP chains are more effective at intermolecular, noncovalent cross-linking of tau. These observations provide an understanding of the initial steps of tau aggregation through interaction with a physiologically relevant aggregation inducer.

scholarly journals Sprr2f protects against renal injury by decreasing the level of reactive oxygen species in female mice

2020 ◽  
Vol 319 (5) ◽  
pp. F876-F884
Author(s):  
Kieu My Huynh ◽  
Anny Chuu-Yun Wong ◽  
Bo Wu ◽  
Marc Horschman ◽  
Hongjuan Zhao ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Renal Injury ◽  
Renal Damage ◽  
Reactive Oxygen ◽  
Protective Role ◽  
Oxygen Species ◽  
Rich Region ◽  
Female Mice ◽  
Proline Rich Region

Renal injury leads to chronic kidney disease, with which women are not only more likely to be diagnosed than men but have poorer outcomes as well. We have previously shown that expression of small proline-rich region 2f ( Sprr2f), a member of the small proline-rich region ( Sprr) gene family, is increased several hundredfold after renal injury using a unilateral ureteral obstruction (UUO) mouse model. To better understand the role of Sprr2f in renal injury, we generated a Sprr2f knockout ( Sprr2f-KO) mouse model using CRISPR-Cas9 technology. Sprr2f-KO female mice showed greater renal damage after UUO compared with wild-type ( Sprr2f-WT) animals, as evidenced by higher hydroxyproline levels and denser collagen staining, indicating a protective role of Sprr2f during renal injury. Gene expression profiling by RNA sequencing identified 162 genes whose expression levels were significantly different between day 0 and day 5 after UUO in Sprr2f-KO mice. Of the 162 genes, 121 genes were upregulated after UUO and enriched with those involved in oxidation-reduction, a phenomenon not observed in Sprr2f-WT animals, suggesting a protective role of Sprr2f in UUO through defense against oxidative damage. Consistently, bilateral ischemia-reperfusion injury resulted in higher serum blood urea nitrogen levels and higher tissue reactive oxygen species in Sprr2f-KO compared with Sprr2f-WT female mice. Moreover, cultured renal epithelial cells from Sprr2f-KO female mice showed lower viability after oxidative damage induced by menadione compared with Sprr2f-WT cells that could be rescued by supplementation with reduced glutathione, suggesting that Sprr2f induction after renal damage acts as a defense against reactive oxygen species.

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