scholarly journals The crystal structure of mouse LC3B in complex with the FYCO1 LIR reveals the importance of the flanking region of the LIR motif

2017 ◽  
Vol 73 (3) ◽  
pp. 130-137 ◽  
Author(s):  
Shunya Sakurai ◽  
Taisuke Tomita ◽  
Toshiyuki Shimizu ◽  
Umeharu Ohto
Keyword(s):  
Crystal Structure ◽  
Coiled Coil ◽  
Adaptor Protein ◽  
Structural Basis ◽  
Core Sequence ◽  
Coiled Coil Domain ◽  
Flanking Sequences ◽  
Flanking Region ◽  
Membrane Components ◽  
Lir Motif

FYVE and coiled-coil domain-containing protein 1 (FYCO1), a multidomain autophagy adaptor protein, mediates microtubule plus-end-directed autophagosome transport by interacting with kinesin motor proteins and with the autophagosomal membrane components microtubule-associated protein 1 light chain 3 (LC3), Rab7 and phosphatidylinositol 3-phosphate (PI3P). To establish the structural basis for the recognition of FYCO1 by LC3, the crystal structure of mouse LC3B in complex with the FYCO1 LC3-interacting region (LIR) motif peptide was determined. Structural analysis showed that the flanking sequences N-terminal and C-terminal to the LIR core sequence of FYCO1, as well as the tetrapeptide core sequence, were specifically recognized by LC3B and contributed to the binding. Moreover, comparisons of related structures revealed a conserved mechanism of FYCO1 recognition by different LC3 isoforms among different species.

scholarly journals Megator, an Essential Coiled-Coil Protein that Localizes to the Putative Spindle Matrix during Mitosis inDrosophila

2004 ◽  
Vol 15 (11) ◽  
pp. 4854-4865 ◽  
Author(s):  
Hongying Qi ◽  
Uttama Rath ◽  
Dong Wang ◽  
Ying-Zhi Xu ◽  
Yun Ding ◽  
...  
Keyword(s):  
Coiled Coil ◽  
Matrix Proteins ◽  
P Element ◽  
Structural Basis ◽  
Spindle Matrix ◽  
Terminal Domain ◽  
Coiled Coil Domain ◽  
Coiled Coil Region ◽  
Spherical Structures ◽  
Spindle Structure

We have used immunocytochemistry and cross-immunoprecipitation analysis to demonstrate that Megator (Bx34 antigen), a Tpr ortholog in Drosophila with an extended coiled-coil domain, colocalizes with the putative spindle matrix proteins Skeletor and Chromator during mitosis. Analysis of P-element mutations in the Megator locus showed that Megator is an essential protein. During interphase Megator is localized to the nuclear rim and occupies the intranuclear space surrounding the chromosomes. However, during mitosis Megator reorganizes and aligns together with Skeletor and Chromator into a fusiform spindle structure. The Megator metaphase spindle persists in the absence of microtubule spindles, strongly implying that the existence of the Megator-defined spindle does not require polymerized microtubules. Deletion construct analysis in S2 cells indicates that the COOH-terminal part of Megator without the coiled-coil region was sufficient for both nuclear as well as spindle localization. In contrast, the NH2-terminal coiled-coil region remains in the cytoplasm; however, we show that it is capable of assembling into spherical structures. On the basis of these findings we propose that the COOH-terminal domain of Megator functions as a targeting and localization domain, whereas the NH2-terminal domain is responsible for forming polymers that may serve as a structural basis for the putative spindle matrix complex.

scholarly journals Model for the architecture of caveolae based on a flexible, net-like assembly of Cavin1 and Caveolin discs

2016 ◽  
Vol 113 (50) ◽  
pp. E8069-E8078 ◽  
Author(s):  
Miriam Stoeber ◽  
Pascale Schellenberger ◽  
C. Alistair Siebert ◽  
Cedric Leyrat ◽  
Ari Helenius ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Complex Formation ◽  
Membrane Binding ◽  
Coiled Coil ◽  
Structural Basis ◽  
Membrane Domains ◽  
Coiled Coil Domain ◽  
Regular Dodecahedron ◽  
Plasma Membrane Domains ◽  
Electron Cryotomography

Caveolae are invaginated plasma membrane domains involved in mechanosensing, signaling, endocytosis, and membrane homeostasis. Oligomers of membrane-embedded caveolins and peripherally attached cavins form the caveolar coat whose structure has remained elusive. Here, purified Cavin1 60S complexes were analyzed structurally in solution and after liposome reconstitution by electron cryotomography. Cavin1 adopted a flexible, net-like protein mesh able to form polyhedral lattices on phosphatidylserine-containing vesicles. Mutating the two coiled-coil domains in Cavin1 revealed that they mediate distinct assembly steps during 60S complex formation. The organization of the cavin coat corresponded to a polyhedral nano-net held together by coiled-coil segments. Positive residues around the C-terminal coiled-coil domain were required for membrane binding. Purified caveolin 8S oligomers assumed disc-shaped arrangements of sizes that are consistent with the discs occupying the faces in the caveolar polyhedra. Polygonal caveolar membrane profiles were revealed in tomograms of native caveolae inside cells. We propose a model with a regular dodecahedron as structural basis for the caveolae architecture.

scholarly journals Phosphorylation of Serine 114 on Atg32 mediates mitophagy

2011 ◽  
Vol 22 (17) ◽  
pp. 3206-3217 ◽  
Author(s):  
Yoshimasa Aoki ◽  
Tomotake Kanki ◽  
Yuko Hirota ◽  
Yusuke Kurihara ◽  
Tetsu Saigusa ◽  
...  
Keyword(s):  
Signal Transduction ◽  
Quality Control ◽  
Significant Role ◽  
Coiled Coil ◽  
Adaptor Protein ◽  
Mitochondrial Quality Control ◽  
Signal Transduction Cascade ◽  
Coiled Coil Domain ◽  
C Terminus ◽  
N Terminus

Mitophagy, which selectively degrades mitochondria via autophagy, has a significant role in mitochondrial quality control. When mitophagy is induced in yeast, mitochondrial residential protein Atg32 binds Atg11, an adaptor protein for selective types of autophagy, and it is recruited into the vacuole along with mitochondria. The Atg11–Atg32 interaction is believed to be the initial molecular step in which the autophagic machinery recognizes mitochondria as a cargo, although how this interaction is mediated is poorly understood. Therefore, we studied the Atg11–Atg32 interaction in detail. We found that the C-terminus region of Atg11, which included the fourth coiled-coil domain, interacted with the N-terminus region of Atg32 (residues 100–120). When mitophagy was induced, Ser-114 and Ser-119 on Atg32 were phosphorylated, and then the phosphorylation of Atg32, especially phosphorylation of Ser-114 on Atg32, mediated the Atg11–Atg32 interaction and mitophagy. These findings suggest that cells can regulate the amount of mitochondria, or select specific mitochondria (damaged or aged) that are degraded by mitophagy, by controlling the activity and/or localization of the kinase that phosphorylates Atg32. We also found that Hog1 and Pbs2, which are involved in the osmoregulatory signal transduction cascade, are related to Atg32 phosphorylation and mitophagy.

scholarly journals Structural basis of NLR activation and innate immune signalling in plants

2022 ◽  
Author(s):  
Natsumi Maruta ◽  
Hayden Burdett ◽  
Bryan Y. J. Lim ◽  
Xiahao Hu ◽  
Sneha Desa ◽  
...  
Keyword(s):  
Immune Responses ◽  
Interleukin 1 ◽  
Three Dimensional ◽  
Coiled Coil ◽  
Innate Immune ◽  
Structural Basis ◽  
Innate Immune Responses ◽  
Oligomeric State ◽  
Coiled Coil Domain ◽  
The Family

AbstractAnimals and plants have NLRs (nucleotide-binding leucine-rich repeat receptors) that recognize the presence of pathogens and initiate innate immune responses. In plants, there are three types of NLRs distinguished by their N-terminal domain: the CC (coiled-coil) domain NLRs, the TIR (Toll/interleukin-1 receptor) domain NLRs and the RPW8 (resistance to powdery mildew 8)-like coiled-coil domain NLRs. CC-NLRs (CNLs) and TIR-NLRs (TNLs) generally act as sensors of effectors secreted by pathogens, while RPW8-NLRs (RNLs) signal downstream of many sensor NLRs and are called helper NLRs. Recent studies have revealed three dimensional structures of a CNL (ZAR1) including its inactive, intermediate and active oligomeric state, as well as TNLs (RPP1 and ROQ1) in their active oligomeric states. Furthermore, accumulating evidence suggests that members of the family of lipase-like EDS1 (enhanced disease susceptibility 1) proteins, which are uniquely found in seed plants, play a key role in providing a link between sensor NLRs and helper NLRs during innate immune responses. Here, we summarize the implications of the plant NLR structures that provide insights into distinct mechanisms of action by the different sensor NLRs and discuss plant NLR-mediated innate immune signalling pathways involving the EDS1 family proteins and RNLs.

Sign in / Sign up

Export Citation Format

Share Document