scholarly journals Structure–function analysis of myomaker domains required for myoblast fusion

2016 ◽  
Vol 113 (8) ◽  
pp. 2116-2121 ◽  
Author(s):  
Douglas P. Millay ◽  
Dilani G. Gamage ◽  
Malgorzata E. Quinn ◽  
Yi-Li Min ◽  
Yasuyuki Mitani ◽  
...  
Keyword(s):  
Muscle Development ◽  
Function Analysis ◽  
Transmembrane Protein ◽  
Specific Protein ◽  
Biochemical Properties ◽  
Myoblast Fusion ◽  
Related Family ◽  
Membrane Spanning ◽  
Cellular Components ◽  
Heterologous Cell

During skeletal muscle development, myoblasts fuse to form multinucleated myofibers. Myomaker [Transmembrane protein 8c (TMEM8c)] is a muscle-specific protein that is essential for myoblast fusion and sufficient to promote fusion of fibroblasts with muscle cells; however, the structure and biochemical properties of this membrane protein have not been explored. Here, we used CRISPR/Cas9 mutagenesis to disrupt myomaker expression in the C2C12 muscle cell line, which resulted in complete blockade to fusion. To define the functional domains of myomaker required to direct fusion, we established a heterologous cell–cell fusion system, in which fibroblasts expressing mutant versions of myomaker were mixed with WT myoblasts. Our data indicate that the majority of myomaker is embedded in the plasma membrane with seven membrane-spanning regions and a required intracellular C-terminal tail. We show that myomaker function is conserved in other mammalian orthologs; however, related family members (TMEM8a and TMEM8b) do not exhibit fusogenic activity. These findings represent an important step toward deciphering the cellular components and mechanisms that control myoblast fusion and muscle formation.

scholarly journals Membrane composition influences the conformation and function of the dopamine transporter in vivo

2019 ◽  
Author(s):  
Wendy M. Fong ◽  
Kevin Erreger ◽  
Se Joon Choi ◽  
India Reddy ◽  
Christopher W. Johnson ◽  
...  
Keyword(s):  
Dopamine Transporter ◽  
Protein Interactions ◽  
Membrane Lipids ◽  
Transmembrane Protein ◽  
Specific Protein ◽  
Biochemical Properties ◽  
Membrane Composition ◽  
Loss Of Function ◽  
And Function

SummaryThe biophysical and biochemical properties of membrane lipids can alter the conformation and function of membrane-spanning proteins, yet the specific, physiological consequence in vivo of changing the membrane milieu for a specific protein has been rarely investigated. Using various genetic approaches to eliminate expression of the membrane-associated protein Flotillin-1, we have found that the lipid environment of the dopamine transporter (DAT) is necessary for mice to respond to amphetamine but not cocaine, because the localization of DAT to cholesterol-rich membranes is required for a DAT conformation that is essential for reverse transport of dopamine. Furthermore, a conditional rather than constitutive loss-of-function approach was necessary to reveal this phenotype, indicating a broader role for membrane-protein interactions that are modulated by Flotillin-1. Taken together, these findings demonstrate how interaction of a transmembrane protein with its membrane environment can regulate distinct events in the vertebrate brain that give rise to specific behavioral outcomes.

scholarly journals Mechanisms of myoblast fusion during muscle development

2015 ◽  
Vol 32 ◽  
pp. 162-170 ◽  
Author(s):  
Ji Hoon Kim ◽  
Peng Jin ◽  
Rui Duan ◽  
Elizabeth H Chen
Keyword(s):  
Muscle Development ◽  
Myoblast Fusion

scholarly journals Structure-Function Analysis of the Endoplasmic Reticulum Oxidoreductase TMX3 Reveals Interdomain Stabilization of the N-terminal Redox-active Domain

2007 ◽  
Vol 282 (46) ◽  
pp. 33859-33867 ◽  
Author(s):  
Johannes Haugstetter ◽  
Michael Andreas Maurer ◽  
Thomas Blicher ◽  
Martin Pagac ◽  
Gerhard Wider ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Protein Disulfide Isomerase ◽  
Function Analysis ◽  
Transmembrane Protein ◽  
Reduced Form ◽  
Disulfide Isomerase ◽  
Binding Domains ◽  
Redox Active ◽  
Protein Disulfide ◽  
Protein Disulfide Isomerase Family

Disulfide bond formation in the endoplasmic reticulum is catalyzed by enzymes of the protein disulfide-isomerase family that harbor one or more thioredoxin-like domains. We recently discovered the transmembrane protein TMX3, a thiol-disulfide oxidoreductase of the protein disulfide-isomerase family. Here, we show that the endoplasmic reticulum-luminal region of TMX3 contains three thioredoxin-like domains, an N-terminal redox-active domain (named a) followed by two enzymatically inactive domains (b and b′). Using the recombinantly expressed TMX3 domain constructs a, ab, and abb′, we compared structural stability and enzymatic properties. By structural and biophysical methods, we demonstrate that the reduced a domain has features typical of a globular folded domain that is, however, greatly destabilized upon oxidization. Importantly, interdomain stabilization by the b domain renders the a domain more resistant toward chemical denaturation and proteolysis in both the oxidized and reduced form. In combination with molecular modeling studies of TMX3 abb′, the experimental results provide a new understanding of the relationship between the multidomain structure of TMX3 and its function as a redox enzyme. Overall, the data indicate that in addition to their role as substrate and co-factor binding domains, redox-inactive thioredoxin-like domains also function in stabilizing neighboring redox-active domains.

scholarly journals The Pichia pastoris PER6 gene product is a peroxisomal integral membrane protein essential for peroxisome biogenesis and has sequence similarity to the Zellweger syndrome protein PAF-1.

1996 ◽  
Vol 16 (5) ◽  
pp. 2527-2536 ◽  
Author(s):  
H R Waterham ◽  
Y de Vries ◽  
K A Russel ◽  
W Xie ◽  
M Veenhuis ◽  
...  
Keyword(s):  
Pichia Pastoris ◽  
Membrane Protein ◽  
Sequence Similarity ◽  
Zellweger Syndrome ◽  
Methylotrophic Yeast ◽  
Integral Membrane Protein ◽  
Biochemical Properties ◽  
Podospora Anserina ◽  
Peroxisome Biogenesis ◽  
Membrane Spanning

We report the cloning of PER6, a gene essential for peroxisome biogenesis in the methylotrophic yeast Pichia pastoris. The PER6 sequence predicts that its product Per6p is a 52-kDa polypeptide with the cysteine-rich C3HC4 motif. Per6p has significant overall sequence similarity with the human peroxisome assembly factor PAF-1, a protein that is defective in certain patients suffering from the peroxisomal disorder Zellweger syndrome, and with car1, a protein required for peroxisome biogenesis and caryogamy in the filamentous fungus Podospora anserina. In addition, the C3HC4 motif and two of the three membrane-spanning segments predicted for Per6p align with the C3HC4 motifs and the two membrane-spanning segments predicted for PAF-1 and car1. Like PAF-1, Per6p is a peroxisomal integral membrane protein. In methanol- or oleic acid-induced cells of per6 mutants, morphologically recognizable peroxisomes are absent. Instead, peroxisomal remnants are observed. In addition, peroxisomal matrix proteins are synthesized but located in the cytosol. The similarities between Per6p and PAF-1 in amino acid sequence and biochemical properties, and between mutants defective in their respective genes, suggest that Per6p is the putative yeast homolog of PAF-1.

Review: The skeletal muscle extracellular matrix: Possible roles in the regulation of muscle development and growth

2012 ◽  
Vol 92 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Sandra G. Velleman ◽  
Jonghyun Shin ◽  
Xuehui Li ◽  
Yan Song
Keyword(s):  
Skeletal Muscle ◽  
Extracellular Matrix ◽  
Growth Factors ◽  
Muscle Cell ◽  
Muscle Development ◽  
Muscle Growth ◽  
Architecture Framework ◽  
Cellular Environment ◽  
Structural Architecture ◽  
Cellular Components

Velleman, S. G., Shin, J., Li, X. and Song, Y. 2012. Review: The skeletal muscle extracellular matrix: Possible roles in the regulation of muscle development and growth. Can. J. Anim. Sci. 92: 1–10. Skeletal muscle fibers are surrounded by an extrinsic extracellular matrix environment. The extracellular matrix is composed of collagens, proteoglycans, glycoproteins, growth factors, and cytokines. How the extracellular matrix influences skeletal muscle development and growth is an area that is not completely understood at this time. Studies on myogenesis have largely been directed toward the cellular components and overlooked that muscle cells secrete a complex extracellular matrix network. The extracellular matrix modulates muscle development by acting as a substrate for muscle cell migration, growth factor regulation, signal transduction of information from the extracellular matrix to the intrinsic cellular environment, and provides a cellular structural architecture framework necessary for tissue function. This paper reviews extracellular matrix regulation of muscle growth with a focus on secreted proteoglycans, cell surface proteoglycans, growth factors and cytokines, and the dynamic nature of the skeletal muscle extracellular matrix, because of its impact on the regulation of muscle cell proliferation and differentiation during myogenesis.

Sources of Performance Information in the Exercise Setting

1990 ◽  
Vol 12 (1) ◽  
pp. 56-65 ◽  
Author(s):  
Vicki Ebbeck
Keyword(s):  
Goal Setting ◽  
Muscle Development ◽  
Information Sources ◽  
Weight Training ◽  
Function Analysis ◽  
Information Source ◽  
Student Feedback ◽  
Sources Of Information ◽  
Perceived Effort ◽  
Gender Groups

This study examined the sources of information used by adult exercisers to judge performance. Of particular interest was the investigation of gender differences. Subjects, 271 adults (174 males, 97 females) who were enrolled in a university weight training program, completed a questionnaire designed to evaluate the importance of 12 information sources in judging weight training performance: instructor feedback, student feedback, student comparison, changes noticed outside the gym, personal attraction toward the activity, degree of perceived effort exerted in the workout, performance in workout, feedback from others not in the class, goal setting, muscle development, workout improvement over time, and ease in learning new skills. Results revealed a significant discriminant function analysis for gender, with six information sources entering the stepwise procedure: goal setting, student feedback, learning, effort, improvement, and changes noticed outside the gym differentiated the gender groups. Males relied more than females on student feedback as an information source to judge performance. Alternatively, females used effort, goal setting, improvement, and learning as information sources more than males.

Effects of Serine/Threonine Protein Phosphatases on Ion Channels in Excitable Membranes

2000 ◽  
Vol 80 (1) ◽  
pp. 173-210 ◽  
Author(s):  
Stefan Herzig ◽  
Joachim Neumann
Keyword(s):  
Ion Channels ◽  
Protein Phosphatase ◽  
Protein Phosphatases ◽  
Direct Interaction ◽  
Specific Protein ◽  
Biochemical Properties ◽  
Future Research ◽  
Regulatory Subunits ◽  
Phosphatase Inhibitors ◽  
Protein Phosphatase Inhibitors

This review deals with the influence of serine/threonine-specific protein phosphatases on the function of ion channels in the plasma membrane of excitable tissues. Particular focus is given to developments of the past decade. Most of the electrophysiological experiments have been performed with protein phosphatase inhibitors. Therefore, a synopsis is required incorporating issues from biochemistry, pharmacology, and electrophysiology. First, we summarize the structural and biochemical properties of protein phosphatase (types 1, 2A, 2B, 2C, and 3–7) catalytic subunits and their regulatory subunits. Then the available pharmacological tools (protein inhibitors, nonprotein inhibitors, and activators) are introduced. The use of these inhibitors is discussed based on their biochemical selectivity and a number of methodological caveats. The next section reviews the effects of these tools on various classes of ion channels (i.e., voltage-gated Ca2+ and Na+ channels, various K+ channels, ligand-gated channels, and anion channels). We delineate in which cases a direct interaction between a protein phosphatase and a given channel has been proven and where a more complex regulation is likely involved. Finally, we present ideas for future research and possible pathophysiological implications.

Heterogeneity of High-molecular-weight Human Salivary Mucins

2000 ◽  
Vol 14 (1) ◽  
pp. 69-75 ◽  
Author(s):  
G.D. Offner ◽  
R.F. Troxler
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Biochemical Properties ◽  
Salivary Proteins ◽  
Molecular Weights ◽  
Structural Framework ◽  
Buccal Epithelial Cells ◽  
Membrane Bound ◽  
Membrane Spanning ◽  
Micro Organisms

The existence of high-molecular-weight glycoproteins in saliva and salivary secretions has been recognized for nearly 30 years. These proteins, called mucins, are essential for oral health and perform many diverse functions in the oral cavity. Mucins have been intensively studied, and much has been learned about their biochemical properties and their interactions with oral micro-organisms and other salivary proteins. In the past several years, the major high-molecular-weight mucin in salivary secretions has been identified as MUC5B, one of a family of 11 human mucin gene products expressed in tissue-specific patterns in the gastrointestinal, respiratory, and reproductive tracts. MUC5B is one of four gel-forming mucins which exist as multimeric proteins with molecular weights greater than 20-40 million daltons. The heavily glycosylated mucin multimers form viscous layers which protect underlying epithelial surfaces from microbial, mechanical, and chemical assault. Another class of mucin molecules, the membrane-bound mucins, is structurally and functionally distinct from the gel-forming mucins. These proteins do not form multimers and can exist as both secreted and membrane-bound forms, with the latter anchored to epithelial cell membranes through a short membrane-spanning domain. In the present work, we show that two of the membrane-bound mucins, MUC1 and MUC4, are expressed in all major human salivary glands as well as in buccal epithelial cells. While the functions of these mucins in the oral environment are not understood, it is possible that they form a structural framework on the cell surface which not only is cytoprotective, but also may serve as a scaffold upon which MUC5B, and possibly other salivary proteins, assemble.

scholarly journals Indirect flight muscles in Drosophila melanogaster as a tractable model to study muscle development and disease

2020 ◽  
Vol 64 (1-2-3) ◽  
pp. 167-173
Author(s):  
Saroj Jawkar ◽  
Upendra Nongthomba
Keyword(s):  
Drosophila Melanogaster ◽  
Muscle Development ◽  
Myoblast Fusion ◽  
Successful Development ◽  
Adult Muscle ◽  
Attachment Sites ◽  
Flight Muscles ◽  
And Function

Myogenesis is a complex multifactorial process leading to the formation of the adult muscle. An amalgamation of autonomous processes including myoblast fusion and myofibrillogenesis, as well as non-autonomous processes, such as innervations from neurons and precise connections with attachment sites, are responsible for successful development and function of muscles. In this review, we describe the development of the indirect flight muscles (IFMs) in Drosophila melanogaster, and highlight the use of the IFMs as a model for studying muscle development and disease, based on recent studies on the development and function of IFMs.

scholarly journals Mind bomb 2, a founder myoblast-specific protein, regulates myoblast fusion and muscle stability

Development ◽  
2008 ◽  
Vol 135 (5) ◽  
pp. 849-857 ◽  
Author(s):  
M. Carrasco-Rando ◽  
M. Ruiz-Gomez
Keyword(s):  
Specific Protein ◽  
Myoblast Fusion
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