scholarly journals How prenylation and S-acylation regulate subcellular targeting and function of ROP GTPases

2011 ◽  
Vol 6 (7) ◽  
pp. 1026-1029 ◽  
Author(s):  
Nadav Sorek ◽  
Yoav Henis ◽  
Shaul Yalovsky
Keyword(s):  
Subcellular Targeting ◽  
And Function

scholarly journals Critical roles for p22phox in the structural maturation and subcellular targeting of Nox3

2007 ◽  
Vol 403 (1) ◽  
pp. 97-108 ◽  
Author(s):  
Yoko Nakano ◽  
Botond Banfi ◽  
Algirdas J. Jesaitis ◽  
Mary C. Dinauer ◽  
Lee-Ann H. Allen ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Subcellular Targeting ◽  
Hek 293 ◽  
Human Embryonic Kidney Cells ◽  
Regulatory Subunits ◽  
Hek 293 Cells ◽  
293 Cells ◽  
A Subunit ◽  
And Function

Otoconia are small biominerals in the inner ear that are indispensable for the normal perception of gravity and motion. Normal otoconia biogenesis requires Nox3, a Nox (NADPH oxidase) highly expressed in the vestibular system. In HEK-293 cells (human embryonic kidney cells) transfected with the Nox regulatory subunits NoxO1 (Nox organizer 1) and NoxA1 (Nox activator 1), functional murine Nox3 was expressed in the plasma membrane and exhibited a haem spectrum identical with that of Nox2, the electron transferase of the phagocyte Nox. In vitro Nox3 cDNA expressed an ∼50 kDa primary translation product that underwent N-linked glycosylation in the presence of canine microsomes. RNAi (RNA interference)-mediated reduction of endogenous p22phox, a subunit essential for stabilization of Nox2 in phagocytes, decreased Nox3 activity in reconstituted HEK-293 cells. p22phox co-precipitated not only with Nox3 and NoxO1 from transfectants expressing all three proteins, but also with NoxO1 in the absence of Nox3, indicating that p22phox physically associated with both Nox3 and with NoxO1. The plasma membrane localization of Nox3 but not of NoxO1 required p22phox. Moreover, the glycosylation and maturation of Nox3 required p22phox expression, suggesting that p22phox was required for the proper biosynthesis and function of Nox3. Taken together, these studies demonstrate critical roles for p22phox at several distinct points in the maturation and assembly of a functionally competent Nox3 in the plasma membrane.

scholarly journals Distinct Roles of N-Terminal Fatty Acid Acylation of the Salinity-Sensor Protein SOS3

2021 ◽  
Vol 12 ◽  
Author(s):  
Irene Villalta ◽  
Elena García ◽  
Dámaso Hornero-Mendez ◽  
Raúl Carranco ◽  
Carlos Tello ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Vascular Plants ◽  
Structural Information ◽  
Subcellular Targeting ◽  
Nuclear Trafficking ◽  
Sodium Efflux ◽  
Sos Pathway ◽  
Net Uptake ◽  
And Function ◽  
Salt Overly Sensitive

The Salt-Overly-Sensitive (SOS) pathway controls the net uptake of sodium by roots and the xylematic transfer to shoots in vascular plants. SOS3/CBL4 is a core component of the SOS pathway that senses calcium signaling of salinity stress to activate and recruit the protein kinase SOS2/CIPK24 to the plasma membrane to trigger sodium efflux by the Na/H exchanger SOS1/NHX7. However, despite the well-established function of SOS3 at the plasma membrane, SOS3 displays a nucleo-cytoplasmic distribution whose physiological meaning is not understood. Here, we show that the N-terminal part of SOS3 encodes structural information for dual acylation with myristic and palmitic fatty acids, each of which commands a different location and function of SOS3. N-myristoylation at glycine-2 is essential for plasma membrane association and recruiting SOS2 to activate SOS1, whereas S-acylation at cysteine-3 redirects SOS3 toward the nucleus. Moreover, a poly-lysine track in positions 7–11 that is unique to SOS3 among other Arabidopsis CBLs appears to be essential for the correct positioning of the SOS2-SOS3 complex at the plasma membrane for the activation of SOS1. The nuclear-localized SOS3 protein had limited bearing on the salt tolerance of Arabidopsis. These results are evidence of a novel S-acylation dependent nuclear trafficking mechanism that contrasts with alternative subcellular targeting of other CBLs by S-acylation.

scholarly journals Exploring Castellaniella defragrans Linalool (De)hydratase-Isomerase for Enzymatic Hydration of Alkenes

Molecules ◽  
2019 ◽  
Vol 24 (11) ◽  
pp. 2092 ◽  
Author(s):  
Matthias Engleder ◽  
Monika Müller ◽  
Iwona Kaluzna ◽  
Daniel Mink ◽  
Martin Schürmann ◽  
...  
Keyword(s):  
Catalytic Mechanism ◽  
Raw Materials ◽  
Low Cost ◽  
Subcellular Targeting ◽  
Plant Metabolites ◽  
Secondary Plant Metabolites ◽  
Expression Host ◽  
Periplasmic Localization ◽  
Mature Enzyme ◽  
And Function

Acyclic monoterpenes constitute a large and highly abundant class of secondary plant metabolites and are, therefore, attractive low-cost raw materials for the chemical industry. To date, numerous biocatalysts for their transformation are known, giving access to highly sought-after monoterpenoids. In view of the high selectivity associated with many of these reactions, the demand for enzymes generating commercially important target molecules is unabated. Here, linalool (de)hydratase-isomerase (Ldi, EC 4.2.1.127) from Castellaniella defragrans was examined for the regio- and stereoselective hydration of the acyclic monoterpene β-myrcene to (S)-(+)-linalool. Expression of the native enzyme in Escherichia coli allowed for identification of bottlenecks limiting enzyme activity, which were investigated by mutating selected residues implied in enzyme assembly and function. Combining these analyses with the recently published 3D structures of Ldi highlighted the precisely coordinated reduction–oxidation state of two cysteine pairs in correct oligomeric assembly and the catalytic mechanism, respectively. Subcellular targeting studies upon fusion of Ldi to different signal sequences revealed the significance of periplasmic localization of the mature enzyme in the heterologous expression host. This study provides biochemical and mechanistic insight into the hydration of β-myrcene, a nonfunctionalized terpene, and emphasizes its potential for access to scarcely available but commercially interesting tertiary alcohols.

Tail-anchored membrane protein SLMAP is a novel regulator of cardiac function at the sarcoplasmic reticulum

2012 ◽  
Vol 302 (5) ◽  
pp. H1138-H1145 ◽  
Author(s):  
Moni Nader ◽  
Bart Westendorp ◽  
Omar Hawari ◽  
Maysoon Salih ◽  
Alexandre F. R. Stewart ◽  
...  
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Qt Interval ◽  
Cardiac Electrophysiology ◽  
Transmembrane Domain ◽  
Left Ventricular ◽  
Confocal Imaging ◽  
Expression Level ◽  
Subcellular Targeting ◽  
Functional Disturbances ◽  
And Function

Sarcolemmal membrane-associated proteins (SLMAPs) are components of cardiac membranes involved in excitation-contraction (E-C) coupling. Here, we assessed the role of SLMAP in cardiac structure and function. We generated transgenic (Tg) mice with cardiac-restricted overexpression of SLMAP1 bearing the transmembrane domain 2 (TM2) to potentially interfere with endogenous SLMAP through homodimerization and subcellular targeting. Histological examination revealed vacuolated myocardium; the severity of which correlated with the expression level of SLMAP1-TM2. High resolution microscopy showed dilation of the sarcoplasmic reticulum/endoplasmic reticulum (SR/ER) and confocal imaging combined with biochemical analysis indicated targeting of SLMAP1-TM2 to the SR/ER membranes and inappropriate homodimerization. Older (28 wk of age) Tg mice exhibited reduced contractility with impaired relaxation as assessed by left ventricle pressure monitoring. The ventricular dysfunction was associated with electrophysiological abnormalities (elongated QT interval). Younger (5 wk of age) Tg mice also exhibited an elongated QT interval with minimal functional disturbances associated with the activation of the fetal gene program. They were less responsive to isoproterenol challenge (ΔdP/d tmax) and developed electrical and left ventricular pressure alternans. The altered electrophysiological and functional disturbances in Tg mice were associated with diminished expression level of calcium cycling proteins of the sarcoplasmic reticulum such as the ryanodine receptor, Ca2+-ATPase, calsequestrin, and triadin (but not phospholamban), as well as significantly reduced calcium uptake in microsomal fractions. These data demonstrate that SLMAP is a regulator of E-C coupling at the level of the SR and its perturbation results in progressive deterioration of cardiac electrophysiology and function.

scholarly journals Subcellular targeting and trafficking of nitric oxide synthases

2006 ◽  
Vol 396 (3) ◽  
pp. 401-409 ◽  
Author(s):  
Stefanie Oess ◽  
Ann Icking ◽  
David Fulton ◽  
Roland Govers ◽  
Werner Müller-Esterl
Keyword(s):  
Nitric Oxide ◽  
Molecular Mechanisms ◽  
No Production ◽  
Subcellular Targeting ◽  
Post Translational Modifications ◽  
Intracellular Targeting ◽  
Highly Active ◽  
Signalling Molecule ◽  
Close Proximity ◽  
And Function

Unlike most other endogenous messengers that are deposited in vesicles, processed on demand and/or secreted in a regulated fashion, NO (nitric oxide) is a highly active molecule that readily diffuses through cell membranes and thus cannot be stored inside the producing cell. Rather, its signalling capacity must be controlled at the levels of biosynthesis and local availability. The importance of temporal and spatial control of NO production is highlighted by the finding that differential localization of NO synthases in cardiomyocytes translates into distinct effects of NO in the heart. Thus NO synthases belong to the most tightly controlled enzymes, being regulated at transcriptional and translational levels, through co- and post-translational modifications, by substrate availability and not least via specific sorting to subcellular compartments, where they are in close proximity to their target proteins. Considerable efforts have been made to elucidate the molecular mechanisms that underlie the intracellular targeting and trafficking of NO synthases, to ultimately understand the cellular pathways controlling the formation and function of this powerful signalling molecule. In the present review, we discuss the mechanisms and triggers for subcellular routing and dynamic redistribution of NO synthases and the ensuing consequences for NO production and action.

Subcellular targeting and function of osteoblast nucleotide pyrophosphatase phosphodiesterase 1

2004 ◽  
Vol 286 (5) ◽  
pp. C1177-C1187 ◽  
Author(s):  
Sucheta M. Vaingankar ◽  
Thomas A. Fitzpatrick ◽  
Kristen Johnson ◽  
James W. Goding ◽  
Michele Maurice ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Transmembrane Protein ◽  
Growth Inhibitor ◽  
Matrix Vesicles ◽  
Subcellular Targeting ◽  
Inorganic Pyrophosphate ◽  
Nucleotide Pyrophosphatase ◽  
Dileucine Motif ◽  
Flanking Region ◽  
And Function

The ectonucleoside pyrophosphatase phosphodiesterase 1 (NPP1/PC-1) is a member of the NPP enzyme family that is critical in regulating mineralization. In certain mineralizing sites of bone and cartilage, membrane-limited vesicles [matrix vesicles (MVs)] provide a sheltered internal environment for nucleation of calcium-containing crystals, including hydroxyapatite. MV formation occurs by budding of vesicles from the plasma membrane of mineralizing cells. The MVs are enriched in proteins that promote mineralization. Paradoxically, NPP1, the type II transmembrane protein that generates the potent hydroxyapatite crystal growth inhibitor inorganic pyrophosphate (PPi), is also enriched in MVs. Although osteoblasts express NPP1, NPP2, and NPP3, only NPP1 is enriched in MVs. Therefore, this study uses mineralizing human osteoblastic SaOS-2 cells, a panel of NPP1 mutants, and NPP1 chimeras with NPP3, which does not concentrate in MVs, to investigate how NPP1 preferentially targets to MVs. We demonstrated that a cytosolic dileucine motif (amino acids 49–50) was critical in localizing NPP1 to regions of the plasma membrane that budded off into MVs. Moreover, transposition of the NPP1 cytoplasmic dileucine motif and flanking region (AAASLLAP) to NPP3 conferred to NPP3 the ability to target to the plasma membrane and, subsequently, concentrate in MVs. Functionally, the cytosolic tail dileucine motif NPP1 mutants lost the ability to support MV PPi concentrations and to suppress calcification. The results identify a specific targeting motif in the NPP1 cytosolic tail that delivers PPi-generating NPP activity to osteoblast MVs for control of calcification.

Biogenesis and activity regulation of protein phosphatase 1

2017 ◽  
Vol 45 (1) ◽  
pp. 89-99 ◽  
Author(s):  
Iris Verbinnen ◽  
Monica Ferreira ◽  
Mathieu Bollen
Keyword(s):  
Protein Phosphatase ◽  
Protein Phosphatase 1 ◽  
Interacting Proteins ◽  
Subcellular Targeting ◽  
Substantial Fraction ◽  
Short Linear Motifs ◽  
Specific Subset ◽  
Linear Motifs ◽  
And Function ◽  
And Control

Protein phosphatase 1 (PP1) is expressed in all eukaryotic cells and catalyzes a substantial fraction of phosphoserine/threonine dephosphorylation reactions. It forms stable complexes with PP1-interacting proteins (PIPs) that guide the phosphatase throughout its life cycle and control its fate and function. The diversity of PIPs is huge (≈200 in vertebrates), and most of them combine short linear motifs to form large and unique interaction interfaces with PP1. Many PIPs have separate domains for PP1 anchoring, PP1 regulation, substrate recruitment and subcellular targeting, which enable them to direct associated PP1 to a specific subset of substrates and mediate acute activity control. Hence, PP1 functions as the catalytic subunit of a large number of multimeric holoenzymes, each with its own subset of substrates and mechanism(s) of regulation.

scholarly journals Role of myristoylation and N-terminal basic residues in membrane association of the human immunodeficiency virus type 1 Nef protein

2006 ◽  
Vol 87 (3) ◽  
pp. 563-571 ◽  
Author(s):  
Matthew Bentham ◽  
Sabine Mazaleyrat ◽  
Mark Harris
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Electrostatic Interactions ◽  
Membrane Association ◽  
Subcellular Targeting ◽  
Immunodeficiency Virus ◽  
And Function

Human immunodeficiency virus type 1 Nef protein is N-terminally myristoylated, a modification reported to be required for the association of Nef with cytoplasmic membranes. As myristate alone is not sufficient to anchor a protein stably into a membrane, it has been suggested that N-terminal basic residues contribute to Nef membrane association via electrostatic interactions with acidic phospholipids. Here, data are presented pertaining to the role of the myristate and basic residues in Nef membrane association, subcellular localization and function. Firstly, by using a biochemical assay for membrane association it was shown that, whereas myristoylation of Nef was not essential, mutation of a cluster of four arginines between residues 17 and 22 reduced membrane association dramatically. Mutation of two lysines at residues 4 and 7 had negligible effect alone, but when combined with the arginine substitutions, abrogated membrane association completely. By using indirect immunofluorescence, it was demonstrated that mutation of either of the two basic clusters altered the subcellular distribution of Nef dramatically. Thirdly, the requirement of the arginine and lysine clusters for Nef-mediated CD4 downmodulation was shown to correlate precisely with membrane association. These data suggest that membrane localization and subcellular targeting of Nef are controlled by a complex interplay of signals at the N terminus of the protein.

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