Isolated p65 protein reproduces membrane binding activity of synaptic vesicles

Neuroreport ◽  
1992 ◽  
Vol 3 (2) ◽  
pp. 177-180 ◽  
Author(s):  
Maurizio Popoli ◽  
Roberto Paternò
2021 ◽  
Author(s):  
Adam S.B. Jalal ◽  
Ngat T. Tran ◽  
Ling J. Wu ◽  
Karunakaran Ramakrishnan ◽  
Martin Rejzek ◽  
...  

2021 ◽  
Author(s):  
Sophie Williams ◽  
Xiulian Yu ◽  
Tao Ni ◽  
Robert Gilbert ◽  
Phillip Stansfeld

Perforin-like proteins (PLPs) play key roles in the mechanisms associated with parasitic disease caused by apicomplexans such as Plasmodium (malaria) and Toxoplasma. The T. gondii PLP1 (TgPLP1) mediates tachyzoite egress from cells, while the five Plasmodium PLPs carry out various roles in the life cycle of the parasite and with respect to the molecular basis of disease. Here we focus on Plasmodium vivax PLP1 and PLP2 (PvPLP1 and PvPLP2) compared to TgPLP1; PvPLP1 is important for invasion of mammalian hosts by the parasite and establishment of a chronic infection, PvPLP2 is important during the symptomatic blood stage of the parasite life cycle. Determination of the crystal structure of the membrane-binding APCβ domain of PvPLP1 reveals notable differences with that of TgPLP1, which are reflected in its inability to bind lipid bilayers in the way that TgPLP1 and PvPLP2 can be shown to. Molecular dynamics simulations combined with site-directed mutagenesis and functional assays allow a dissection of the binding interactions of TgPLP1 and PvPLP2 on lipid bilayers, and reveal a similar tropism for lipids found enriched in the inner leaflet of the mammalian plasma membrane. In addition to this shared mode of membrane binding PvPLP2 displays a secondary synergistic interaction side-on from its principal bilayer interface. This study underlines the substantial differences between the biophysical properties of the APCβ domains of Apicomplexan PLPs, which reflect their significant sequence diversity. Such differences will be important factors in determining the cell targeting and membrane-binding activity of the different proteins, in their different developmental roles within parasite life cycles.


1987 ◽  
Vol 105 (4) ◽  
pp. 1741-1751 ◽  
Author(s):  
L J Wuestehube ◽  
E J Luna

F-actin affinity chromatography and immunological techniques are used to identify actin-binding proteins in purified Dictyostelium discoideum plasma membranes. A 17-kD integral glycoprotein (gp17) consistently elutes from F-actin columns as the major actin-binding protein under a variety of experimental conditions. The actin-binding activity of gp17 is identical to that of intact plasma membranes: it resists extraction with 0.1 N NaOH, 1 mM dithiothreitol (DTT); it is sensitive to ionic conditions; it is stable over a wide range of pH; and it is eliminated by proteolysis, denaturation with heat, or treatment with DTT and N-ethylmaleimide. gp17 may be responsible for much of the actin-binding activity of plasma membranes since monovalent antibody fragments (Fab) directed primarily against gp17 inhibit actin-membrane binding by 96% in sedimentation assays. In contrast, Fab directed against cell surface determinants inhibit binding by only 0-10%. The actin-binding site of gp17 appears to be located on the cytoplasmic surface of the membrane since Fab against this protein continue to inhibit 96% of actin-membrane binding even after extensive adsorption against cell surfaces. gp17 is abundant in the plasma membrane, constituting 0.4-1.0% of the total membrane protein. A transmembrane orientation of gp17 is suggested since, in addition to the cytoplasmic localization of the actin-binding site, extracellular determinants of gp17 are identified. gp17 is surface-labeled by sulfo-N-hydroxy-succinimido-biotin, a reagent that cannot penetrate the cell membrane. Also, gp17 is glycosylated since it is specifically bound by the lectin, concanavalin A. We propose that gp17 is a major actin-binding protein that is important for connecting the plasma membrane to the underlying microfilament network. Therefore, we have named this protein "ponticulin" from the Latin word, ponticulus, which means small bridge.


2016 ◽  
Author(s):  
Yolanda Olmos ◽  
Anna Perdrix ◽  
Jeremy G Carlton

AbstractAmongst other cellular functions, the Endosomal Sorting Complex Required for Transport-III (ESCRT-III) machinery controls nuclear envelope (NE) reformation during mitotic exit by sealing holes in the reforming NE. ESCRT-III also acts to repair this organelle upon migration-induced rupture. The ESCRT-III component CHMP7 is responsible for recruitment of ESCRT-III to the NE. Here, we show that the N-terminus of CHMP7, comprising tandem Winged Helix (WH)-domains, is a membrane-binding module. This activity allows CHMP7 to bind to the Endoplasmic Reticulum (ER), an organelle continuous with the NE, and provides a platform to direct NE-recruitment of ESCRT-III during mitotic exit. Point mutations that disrupt membrane-binding prevent CHMP7 localising to the ER and its subsequent enrichment at the reforming NE. These mutations prevent both assembly of downstream ESCRT-III components at the reforming NE and proper establishment of post-mitotic nucleo-cytoplasmic compartmentalisation. These data identify a novel membrane-binding activity within an ESCRT-III subunit that is essential for post-mitotic nuclear regeneration.One Sentence SummaryCHMP7’s atypical N-terminus is a membrane-binding module that allows assembly and function of ESCRT-III at the nuclear envelope during mitotic exit.


2019 ◽  
Vol 431 (11) ◽  
pp. 2112-2126 ◽  
Author(s):  
Faraz M. Harsini ◽  
Anthony A. Bui ◽  
Anne M. Rice ◽  
Sukanya Chebrolu ◽  
Kerry L. Fuson ◽  
...  

1997 ◽  
Vol 323 (2) ◽  
pp. 421-425 ◽  
Author(s):  
Mitsunori FUKUDA ◽  
Toshio KOJIMA ◽  
Katsuhiko MIKOSHIBA

Synaptotagmins are Ca2+-and phospholipid-binding proteins of synaptic vesicles that might function as Ca2+ receptors for neurotransmitter release via their first C2 (C2A) domain. Here we describe the effect of Mg2+ on phospholipid binding to the C2A domains of multiple synaptotagmins (II–VI), and demonstrate that only synaptotagmin III can bind negatively charged phospholipids [phosphatidylserine (PS) and phosphatidylinositol] in a Mg2+-dependent manner. The Mg2+-dependent interaction with PS was found to have an EC50 of approx. 30 μM Mg2+, which is comparable to that of Sr2+ and Ba2+ (EC50 values of approx. 10 μM). This binding property of the C2A domain is specific to synaptotagmin III, because none of the C2A domains of other proteins, such as rabphilin 3A, Doc2α, Doc2β or Gap1m, showed phospholipid binding activity in the presence of 1 mM Mg2+. Our results suggest that synaptotagmin III is involved in presynaptic functions different from those of synaptotagmins I and II.


ACS Omega ◽  
2017 ◽  
Vol 2 (11) ◽  
pp. 7482-7492 ◽  
Author(s):  
Daniela Ciumac ◽  
Richard A. Campbell ◽  
Luke A. Clifton ◽  
Hai Xu ◽  
Giovanna Fragneto ◽  
...  

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