scholarly journals Role of Glycoproteins during Fruit Ripening and Seed Development

Cells ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 2095
Author(s):  
Angela Mendez-Yañez ◽  
Patricio Ramos ◽  
Luis Morales-Quintana

Approximately thirty percent of the proteins synthesized in animal or plant cells travel through the secretory pathway. Seventy to eighty percent of those proteins are glycosylated. Thus, glycosylation is an important protein modification that is related to many cellular processes, such as differentiation, recognition, development, signal transduction, and immune response. Additionally, glycosylation affects protein folding, solubility, stability, biogenesis, and activity. Specifically, in plants, glycosylation has recently been related to the fruit ripening process. This review aims to provide valuable information and discuss the available literature focused on three principal topics: (I) glycosylations as a key posttranslational modification in development in plants, (II) experimental and bioinformatics tools to analyze glycosylations, and (III) a literature review related to glycosylations in fruit ripening. Based on these three topics, we propose that it is necessary to increase the number of studies related to posttranslational modifications, specifically protein glycosylation because the specific role of glycosylation in the posttranslational process and how this process affects normal fruit development and ripening remain unclear to date.

2012 ◽  
Vol 2012 ◽  
pp. 1-21 ◽  
Author(s):  
Cheng Jin

Glycosylation is a conserved posttranslational modification that is found in all eukaryotes, which helps generate proteins with multiple functions. Our knowledge of glycosylation mainly comes from the investigation of the yeastSaccharomyces cerevisiaeand mammalian cells. However, during the last decade, glycosylation in the human pathogenic moldAspergillus fumigatushas drawn significant attention. It has been revealed that glycosylation inA. fumigatusis crucial for its growth, cell wall synthesis, and development and that the process is more complicated than that found in the budding yeastS. cerevisiae. The present paper implies that the investigation of glycosylation inA. fumigatusis not only vital for elucidating the mechanism of fungal cell wall synthesis, which will benefit the design of new antifungal therapies, but also helps to understand the role of protein glycosylation in the development of multicellular eukaryotes. This paper describes the advances in functional analysis of protein glycosylation inA. fumigatus.


2011 ◽  
Vol 300 (5) ◽  
pp. F1062-F1073 ◽  
Author(s):  
Hanne B. Moeller ◽  
Emma T. B. Olesen ◽  
Robert A. Fenton

The cellular functions of many eukaryotic membrane proteins, including the vasopressin-regulated water channel aquaporin-2 (AQP2), are regulated by posttranslational modifications. In this article, we discuss the experimental discoveries that have advanced our understanding of how posttranslational modifications affect AQP2 function, especially as they relate to the role of AQP2 in the kidney. We review the most recent data demonstrating that glycosylation and, in particular, phosphorylation and ubiquitination are mechanisms that regulate AQP2 activity, subcellular sorting and distribution, degradation, and protein interactions. From a clinical perspective, posttranslational modification resulting in protein misrouting or degradation may explain certain forms of nephrogenic diabetes insipidus. In addition to providing major insight into the function and dynamics of renal AQP2 regulation, the analysis of AQP2 posttranslational modification may provide general clues as to the role of posttranslational modification for regulation of other membrane proteins.


1987 ◽  
Vol 245 (1) ◽  
pp. 243-250 ◽  
Author(s):  
S P Wolff ◽  
R T Dean

Monosaccharide autoxidation (a transition metal-catalysed process that generates H2O2 and ketoaldehydes) appears to contribute to protein modification by glucose in vitro. The metal-chelating agent diethylenetriaminepenta-acetic acid (DETAPAC), which inhibits glucose autoxidation, also reduces the covalent attachment of glucose to bovine serum albumin. A maximal 45% inhibition of covalent attachment was observed, but this varied with glucose and DETAPAC concentrations in a complex fashion, suggesting at least two modes of attachment. The extent of inhibition of the metal-catalysed pathway correlated with the extent of inhibition of glycosylation-associated chromo- and fluorophore development. DETAPAC also inhibited tryptophan fluorescence quenching associated with glycosylation. Conversely, ketoaldehydes analogous to those produced by glucose autoxidation, but generated by 60Co irradiation, bound avidly to albumin and accelerated browning reactions. It is therefore suggested that a component of protein glycosylation is dependent upon glucose autoxidation and subsequent covalent attachment of ketoaldehydes. The process of glucose autoxidation, or ketoaldehydes derived therefrom, appear to be important in chromophoric and fluorophoric alterations. It is noted, consistent with these observations, that the chemical evidence for the currently accepted ‘Amadori’ product derived from the reaction of glucose with protein amino groups is consistent also with the structure expected for the attachment of a glucose-derived ketoaldehyde to protein. The concept of ‘autoxidative glycosylation’ is briefly discussed in relation to oxidative stress in diabetes mellitus.


2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Jinlin Liu ◽  
Li Zhong ◽  
Rui Guo

Cardiovascular disease (CVD) is the leading cause of death in the world. The mechanism behind CVDs has been studied for decades; however, the pathogenesis is still controversial. Mitochondrial homeostasis plays an essential role in maintaining the normal function of the cardiovascular system. The alterations of any protein function in mitochondria may induce abnormal mitochondrial quality control and unexpected mitochondrial dysfunction, leading to CVDs. Posttranslational modifications (PTMs) affect protein function by reversibly changing their conformation. This review summarizes how common and novel PTMs influence the development of CVDs by regulating mitochondrial quality control. It provides not only ideas for future research on the mechanism of some types of CVDs but also ideas for CVD treatments with therapeutic potential.


Open Biology ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 200054 ◽  
Author(s):  
Ana Talamillo ◽  
Leiore Ajuria ◽  
Marco Grillo ◽  
Orhi Barroso-Gomila ◽  
Ugo Mayor ◽  
...  

SUMOylation—protein modification by the small ubiquitin-related modifier (SUMO)—affects several cellular processes by modulating the activity, stability, interactions or subcellular localization of a variety of substrates. SUMO modification is involved in most cellular processes required for the maintenance of metabolic homeostasis. Cholesterol is one of the main lipids required to preserve the correct cellular function, contributing to the composition of the plasma membrane and participating in transmembrane receptor signalling. Besides these functions, cholesterol is required for the synthesis of steroid hormones, bile acids, oxysterols and vitamin D. Cholesterol levels need to be tightly regulated: in excess, it is toxic to the cell, and the disruption of its homeostasis is associated with various disorders like atherosclerosis and cardiovascular diseases. This review focuses on the role of SUMO in the regulation of proteins involved in the metabolism of cholesterol.


2020 ◽  
Vol 21 (6) ◽  
pp. 544-552 ◽  
Author(s):  
Hongrong Wu ◽  
Tianjiao Li ◽  
Jianfeng Zhao

GRASP55 was first found as Golgi cisternae stacking protein. Due to the crucial role of Golgi in vesicular trafficking and protein modification, GRASP55 was found to function in these two aspects. Further investigation revealed that GRASP55 also participates in the unconventional secretory pathway under stress. Moreover, GRASP55 is involved in autophagy initiation and autophagosome maturation, as well as cell activity.


2005 ◽  
Vol 69 (3) ◽  
pp. 393-425 ◽  
Author(s):  
Jerry Eichler ◽  
Michael W. W. Adams

SUMMARY One of the first hurdles to be negotiated in the postgenomic era involves the description of the entire protein content of the cell, the proteome. Such efforts are presently complicated by the various posttranslational modifications that proteins can experience, including glycosylation, lipid attachment, phosphorylation, methylation, disulfide bond formation, and proteolytic cleavage. Whereas these and other posttranslational protein modifications have been well characterized in Eucarya and Bacteria, posttranslational modification in Archaea has received far less attention. Although archaeal proteins can undergo posttranslational modifications reminiscent of what their eucaryal and bacterial counterparts experience, examination of archaeal posttranslational modification often reveals aspects not previously observed in the other two domains of life. In some cases, posttranslational modification allows a protein to survive the extreme conditions often encountered by Archaea. The various posttranslational modifications experienced by archaeal proteins, the molecular steps leading to these modifications, and the role played by posttranslational modification in Archaea form the focus of this review.


2021 ◽  
Author(s):  
Nakita Buenbrazo

Protein glycosylation is the most abundant and diverse protein modification that occurs in all domains of life. It is defined as the covalent attachment of a carbohydrate moiety to a specific amino acid on a target protein. The functional role of this attachment is implicated in and spans various cell processes from cell signaling, cell defense, and pathogenesis – to name a few. A specific type of protein glycosylation, called protein O-mannosylation (POM) is a process found to be conserved from bacteria to man. In humans, POM is required for healthy cell function, and the absence of POM can cause fatal diseases. Certain prokaryotic species possess a related POM system, but it is poorly understood. It is our hypothesis that the analysis of the POM system in simpler organisms can aid in the characterization of this process and the functional role of the mannosylated proteins that are produced. However, the protocols to prove this theory do not yet exist. This thesis establishes a collection of developed protocols that can be used to characterize the POM systems from gram-positive species Corynebacterium glutamicum and Cellulomonas fimi. In addition the first ever evidence of a C. fimi glycoprotein being glycosylated by the endogenous C. glutamicum POM system is provided.


2017 ◽  
Vol 2017 ◽  
pp. 1-15 ◽  
Author(s):  
Viktória Fisi ◽  
Attila Miseta ◽  
Tamás Nagy

O-linked N-acetylglucosamine (O-GlcNAc) is a posttranslational modification that is increasingly recognized as a signal transduction mechanism. Unlike other glycans, O-GlcNAc is a highly dynamic and reversible process that involves the addition and removal of a single N-acetylglucosamine molecule to Ser/Thr residues of proteins. UDP-GlcNAc—the direct substrate for O-GlcNAc modification—is controlled by the rate of cellular metabolism, and thus O-GlcNAc is dependent on substrate availability. Serving as a feedback mechanism, O-GlcNAc influences the regulation of insulin signaling and glucose transport. Besides nutrient sensing, O-GlcNAc was also implicated in the regulation of various physiological and pathophysiological processes. Due to improvements of mass spectrometry techniques, more than one thousand proteins were detected to carry the O-GlcNAc moiety; many of them are known to participate in the regulation of metabolites, ions, or protein transport across biological membranes. Recent studies also indicated that O-GlcNAc is involved in stress adaptation; overwhelming evidences suggest that O-GlcNAc levels increase upon stress. O-GlcNAc elevation is generally considered to be beneficial during stress, although the exact nature of its protective effect is not understood. In this review, we summarize the current data regarding the oxidative stress-related changes of O-GlcNAc levels and discuss the implications related to membrane trafficking.


2005 ◽  
Vol 4 (1) ◽  
pp. 147-155 ◽  
Author(s):  
Yen-Ping Hsueh ◽  
Wei-Chiang Shen

ABSTRACT Fungal pheromones function during the initial recognition stage of the mating process. One type of peptide pheromone identified in ascomycetes and basidiomycetes terminates in a conserved CAAX motif and requires extensive posttranslational modifications to become mature and active. A well-studied representative is the a-factor of Saccharomyces cerevisiae. Unlike the typical secretory pathway utilized by most peptides, an alternative mechanism involving the ATP-binding cassette transporter Ste6 is used for the export of mature a-factor. Cryptococcus neoformans, a bipolar human pathogenic basidiomycete, produces CAAX motif-containing lipopeptide pheromones in both MAT a and MATα cells. Virulence studies with a congenic pair of C. neoformans serotype D strains have shown that MATα cells are more virulent than MAT a cells. Characterization of the MATα pheromones indicated that an autocrine signaling loop may contribute to the differentiation and virulence of MATα cells. To further address the role of pheromones in the signaling loop, we identified a STE6 homolog in the C. neoformans genome and determined its function by gene disruption. The ste6 mutants in either mating-type background showed partially impaired mating functions, and mating was completely abolished in a bilateral mutant cross. Surprisingly, the MATα ste6 mutant does not exhibit a defect in monokaryotic fruiting, suggesting that the activation of the autocrine signaling loop by the pheromone is via a Ste6-independent mechanism. MFα pheromone itself is essential for this process and could induce the signaling response intracellularly in MATα cells. Our data demonstrate that Ste6 is evolutionarily conserved for mating and is not required for monokaryotic fruiting in C. neoformans.


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