scholarly journals Netrins and neogenin promote myotube formation

2004 ◽  
Vol 167 (3) ◽  
pp. 493-504 ◽  
Author(s):  
Jong-Sun Kang ◽  
Min-Jeong Yi ◽  
Wei Zhang ◽  
Jessica L. Feinleib ◽  
Francesca Cole ◽  
...  
Keyword(s):  
Cell Surface ◽  
Myogenic Differentiation ◽  
Surface Proteins ◽  
Myotube Formation ◽  
Skeletal Myoblasts ◽  
Ig Superfamily ◽  
Multistep Process ◽  
A Cell ◽  
Multinucleated Myotubes ◽  
Autocrine Mechanism

Differentiation of skeletal myoblasts into multinucleated myotubes is a multistep process orchestrated by several families of transcription factors, including myogenic bHLH and NFAT proteins. The activities of these factors and formation of myotubes are regulated by signal transduction pathways, but few extracellular factors that might initiate such signals have been identified. One exception is a cell surface complex containing promyogenic Ig superfamily members (CDO and BOC) and cadherins. Netrins and their receptors are established regulators of axon guidance, but little is known of their function outside the nervous system. We report here that myoblasts express the secreted factor netrin-3 and its receptor, neogenin. These proteins stimulate myotube formation and enhance myogenic bHLH- and NFAT-dependent transcription. Furthermore, neogenin binds to CDO in a cis fashion, and myoblasts lacking CDO are defective in responding to recombinant netrin. It is proposed that netrin-3 and neogenin may promote myogenic differentiation by an autocrine mechanism as components of a higher order complex of several promyogenic cell surface proteins.

scholarly journals Involvement of a cell surface protein and an ecto-protein kinase in myogenesis

1991 ◽  
Vol 279 (2) ◽  
pp. 475-482 ◽  
Author(s):  
X Y Chen ◽  
T C Y Lo
Keyword(s):  
Protein Kinase ◽  
Cell Surface ◽  
Myogenic Differentiation ◽  
Morphological Differentiation ◽  
Surface Protein ◽  
Chemical Reagents ◽  
Defective Mutant ◽  
A Cell ◽  
One Step ◽  
Multinucleated Myotubes

Myogenic differentiation is composed of a sequential cascade of multiple steps leading to the formation of multinucleated myotubes. The interference with any one step would abolish myogenesis. The present investigation examined the cell surface components which might be involved in myogenesis. Studies with subconfluent day 2 cultures of rat L6 myoblasts revealed that a cell surface 112 kDa protein was phosphorylated by a Ca(2+)-, F(-)- and Mg(2+)-dependent ecto-protein kinase [Chen & Lo (1991) Biochem. J. 279, 467-474]. We have shown in the present investigation that adequate ATP was present on the cell surface for efficient functioning of this ecto-protein kinase. The phosphorylation of the 112 kDa protein by this ecto-protein kinase was decrease dramatically in confluent cells and in multinucleated myotubes. The following evidence suggests that both the 112 kDa protein and the ecto-protein kinase may play important roles in myogenesis. (i) The highest phosphorylation activity was observed in subconfluent cultures, i.e. before the onset of morphological differentiation. (ii) Treatment of cells with chemical reagents resulted in a corresponding decrease in the ecto-protein kinase, the 112 kDa protein, the phosphorylated 112 kDa protein (p112) and the ability to form myotubes. (iii) The level of p112 in a conditional myogenesis-defective mutant corresponded with the cells' eventual ability to differentiate. (iv) A mutant defective in the ecto-protein kinase was impaired in the phosphorylation of the 112 kDa protein and in myogenesis. (v) A mutant containing only residual levels of the 112 kDa protein was deficient in both p112 and myogenesis. (vi) Since the level of p112 was normal in another myogenesis-defective mutant, the phosphorylation of this protein was not likely to be a consequence of myogenic differentiation. The above findings suggest that the ecto-protein kinase and the 112 kDa protein may directly or indirectly be associated with the myogenic pathway. Since the levels of the ecto-protein kinase, the 112 kDa protein and p112 decreased dramatically upon the formation of myotubes, these proteins were probably not required once morphological differentiation had been initiated.

scholarly journals The in silico human surfaceome

2018 ◽  
Vol 115 (46) ◽  
pp. E10988-E10997 ◽  
Author(s):  
Damaris Bausch-Fluck ◽  
Ulrich Goldmann ◽  
Sebastian Müller ◽  
Marc van Oostrum ◽  
Maik Müller ◽  
...  
Keyword(s):  
Cell Surface ◽  
In Silico ◽  
Embryonic Stem ◽  
Surface Protein ◽  
Surface Proteins ◽  
Cell Surface Protein ◽  
Cell Surface Proteins ◽  
A Cell ◽  
Visualization Tools ◽  
Protein Classes

Cell-surface proteins are of great biomedical importance, as demonstrated by the fact that 66% of approved human drugs listed in the DrugBank database target a cell-surface protein. Despite this biomedical relevance, there has been no comprehensive assessment of the human surfaceome, and only a fraction of the predicted 5,000 human transmembrane proteins have been shown to be located at the plasma membrane. To enable analysis of the human surfaceome, we developed the surfaceome predictor SURFY, based on machine learning. As a training set, we used experimentally verified high-confidence cell-surface proteins from the Cell Surface Protein Atlas (CSPA) and trained a random forest classifier on 131 features per protein and, specifically, per topological domain. SURFY was used to predict a human surfaceome of 2,886 proteins with an accuracy of 93.5%, which shows excellent overlap with known cell-surface protein classes (i.e., receptors). In deposited mRNA data, we found that between 543 and 1,100 surfaceome genes were expressed in cancer cell lines and maximally 1,700 surfaceome genes were expressed in embryonic stem cells and derivative lines. Thus, the surfaceome diversity depends on cell type and appears to be more dynamic than the nonsurface proteome. To make the predicted surfaceome readily accessible to the research community, we provide visualization tools for intuitive interrogation (wlab.ethz.ch/surfaceome). The in silico surfaceome enables the filtering of data generated by multiomics screens and supports the elucidation of the surfaceome nanoscale organization.

Regulation of the activity of a calcium-activated neutral protease during differentiation of skeletal myoblasts

1981 ◽  
Vol 59 (9) ◽  
pp. 743-747 ◽  
Author(s):  
Harjeet Kaur ◽  
Bishnu D. Sanwal
Keyword(s):  
Cell Line ◽  
Plasminogen Activator ◽  
Protease Activity ◽  
Cathepsin D ◽  
Potent Inhibitor ◽  
Neutral Protease ◽  
Myotube Formation ◽  
Skeletal Myoblasts ◽  
A Cell ◽  
Mode Of Regulation

A calcium-activated neutral protease activity appears concomitantly with myotube formation during the differentiation of a cell line of rat skeletal myoblasts. Other proteases such as cathepsin D and plasminogen activator, however, do not show any changes in their activities. The appearance of the protease is not fusion dependent, as judged by assays of fusion defective myoblast mutants. The formation of the protease is suppressed along with differentiation in the presence of 5-bromodeoxyuridine. Undifferentiated myoblasts contain a potent inhibitor of the protease. The inhibitor, which is probably proteinaceous in nature, is lost during the differentiation of the cells into myotubes. This mode of regulation of an enzyme during differentiation seems so far to be an unique example of its kind.

scholarly journals A high-molecular-mass cell-surface protein from Lactobacillus reuteri 1063 adheres to mucus components The GenBank accession number for the sequence reported in this paper is AF120104.

Microbiology ◽  
2002 ◽  
Vol 148 (2) ◽  
pp. 433-442 ◽  
Author(s):  
Stefan Roos ◽  
Hans Jonsson
Keyword(s):  
Cell Surface ◽  
Lactobacillus Reuteri ◽  
Surface Protein ◽  
Surface Proteins ◽  
Cell Surface Protein ◽  
Intestinal Mucus ◽  
A Cell ◽  
Molecular Masses ◽  
Ph Range

A gene from Lactobacillus reuteri 1063 encoding a cell-surface protein, designated Mub, that adheres to mucus components in vitro has been cloned and sequenced. The deduced amino acid sequence of Mub (358 kDa) shows the presence of 14 approximately 200 aa repeats and features typical for other cell-surface proteins of Gram-positive bacteria. Fusion proteins consisting of different repeats of Mub and the maltose-binding protein (MBP) were produced. These proteins adhered to pig mucus components, with molecular masses ranging from <0·1 to >2 MDa, to pig gastric mucin and to hen intestinal mucus. The binding of Mub to mucus components occurred in the pH range 3–7·4, with maximum binding at pH 4–5 and could be partly inhibited by the glycoprotein fetuin. Affinity-purified antibodies against recombinant Mub were used in immunofluorescence microscopy to demonstrate the presence of Mub on the cell surface of strain 1063. By using the antibodies in a Western blot analysis, Mub could also be detected in the growth medium. The results implicate Mub as a cell-surface protein that is involved in Lactobacillus interactions with mucin and in colonization of the digestive tract.

scholarly journals Functional correlation between cell adhesive properties and some cell surface proteins.

1977 ◽  
Vol 75 (2) ◽  
pp. 464-474 ◽  
Author(s):  
M Takeichi
Keyword(s):  
Cell Surface ◽  
Chinese Hamster ◽  
Surface Protein ◽  
Surface Proteins ◽  
Adhesive Properties ◽  
Cell Surface Proteins ◽  
Morphological Studies ◽  
Chinese Hamster V79 Cells ◽  
A Cell ◽  
In Cells

The adhesive properties of Chinese hamster V79 cells were analyzed and characterized by various cell dissociation treatments. The comparisons of aggregability among cells dissociated with EDTA, trypsin + Ca2+, and trypsin + EDTA, revealed that these cells have two adhesion mechanisms, a Ca2+-independent and a Ca2+-dependent one. The former did not depend on temperature, whereas the latter occurred only at physiological temperatures. Both mechanisms were trypsin sensitive, but the Ca2+-dependent one was protected by Ca2+ against trypsinization. In morphological studies, the Ca2+-independent adhesion appeared to be a simple agglutination or flocculation of cells, whereas the Ca2+-dependent adhesion seemed to be more physiological, being accompanied by cell deformation resulting in the increase of contact area between adjacent cells. Lactoperoxidase-catalyzed iodination of cell surface proteins revealed that several proteins are more intensely labeled in cells with Ca2+-independent adhesiveness than in cells without that property. It was also found that a cell surface protein with a molecular weight of approximately 150,000 is present only in cells with Ca2+-dependent adhesiveness. The iodination and trypsinization of this protein were protected by Ca2+, suggesting its reactivity to Ca2+. Possible mechanisms for each adhesion property are discussed, taking into account the correlation of these proteins with cell adhesiveness.

scholarly journals Large remodeling of the Myc-induced cell surface proteome in B cells and prostate cells creates new opportunities for immunotherapy

2021 ◽  
Vol 118 (4) ◽  
pp. e2018861118
Author(s):  
Wentao Chen ◽  
Kurt Yun Mou ◽  
Paige Solomon ◽  
Rahul Aggarwal ◽  
Kevin K. Leung ◽  
...  
Keyword(s):  
Cell Surface ◽  
B Cell ◽  
Cell Lines ◽  
Surface Proteins ◽  
Cell Type ◽  
Hematological Cancers ◽  
A Cell ◽  
Surface Proteome ◽  
The Impact ◽  
Cell Surface Proteome

MYC is a powerful transcription factor overexpressed in many human cancers including B cell and prostate cancers. Antibody therapeutics are exciting opportunities to attack cancers but require knowledge of surface proteins that change due to oncogene expression. To identify how MYC overexpression remodels the cell surface proteome in a cell autologous fashion and in different cell types, we investigated the impact of MYC overexpression on 800 surface proteins in three isogenic model cell lines either of B cell or prostate cell origin engineered to have high or low MYC levels. We found that MYC overexpression resulted in dramatic remodeling (both up- and down-regulation) of the cell surfaceome in a cell type-dependent fashion. We found systematic and large increases in distinct sets of >80 transporters including nucleoside transporters and nutrient transporters making cells more sensitive to toxic nucleoside analogs like cytarabine, commonly used for treating hematological cancers. Paradoxically, MYC overexpression also increased expression of surface proteins driving cell turnover such as TNFRSF10B, also known as death receptor 5, and immune cell attacking signals such as the natural killer cell activating ligand NCR3LG1, also known as B7-H6. We generated recombinant antibodies to these two targets and verified their up-regulation in MYC overexpression cell lines and showed they were sensitive to bispecific T cell engagers (BiTEs). Our studies demonstrate how MYC overexpression leads to dramatic bidirectional remodeling of the surfaceome in a cell type-dependent but functionally convergent fashion and identify surface targets or combinations thereof as possible candidates for cytotoxic metabolite or immunotherapy.

scholarly journals Cell-specific Bioorthogonal Tagging of Glycoproteins in Co-culture

2021 ◽  
Author(s):  
Anna Cioce ◽  
Beatriz Calle ◽  
Andrea Marchesi ◽  
Ganka Bineva-Todd ◽  
Helen Flynn ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Cell Surface ◽  
Cell Line ◽  
Specific Protein ◽  
Surface Proteins ◽  
Cancer Development ◽  
Biological Processes ◽  
Culture Studies ◽  
Cell Surface Proteins ◽  
A Cell

Interactions between cells fundamentally impact biological processes. In cancer development, such interactions define key stages of disease that cannot be adequately recapitulated in cell monoculture. Complex co-culture studies have been key to unraveling the complexity of these processes, usually by sorting cells and transcriptome or bulk proteome analyses. However, these methods invariably lead to sample loss and do not capture aberrant glycosylation as an important corollary of cancer formation. Here, we report the development of Bio-Orthogonal Cell line-specific Tagging of Glycoproteins (BOCTAG). Cells are equipped with a biosynthetic AND gate that uses bioorthogonally tagged sugars to generate glycosylation precursors. The cellular glycosylation machinery then introduces bioorthogonal tags into glycoproteins exclusively in cell lines expressing the enzymes of the biosynthetic AND gate. Modification with clickable reporter moieties allows for imaging or enrichment with mass spectrometry-proteomics in a cell-specific fashion. Making use of glycans as a property of most cell surface proteins, we use BOCTAG as an efficient means for cell-specific protein tracing.

scholarly journals VP7 Mediates the Interaction of Rotaviruses with Integrin αvβ3 through a Novel Integrin-Binding Site

2004 ◽  
Vol 78 (20) ◽  
pp. 10839-10847 ◽  
Author(s):  
Selene Zárate ◽  
Pedro Romero ◽  
Rafaela Espinosa ◽  
Carlos F. Arias ◽  
Susana López
Keyword(s):  
Sialic Acid ◽  
Cell Surface ◽  
Surface Protein ◽  
Integrin Αvβ3 ◽  
Surface Proteins ◽  
Binding Motif ◽  
Independent Manner ◽  
Multistep Process ◽  
Integrin Binding Site ◽  
Viral Surface Protein

ABSTRACT Rotavirus entry is a complex multistep process that depends on the trypsin cleavage of the virus spike protein VP4 into polypeptides VP5 and VP8 and on the interaction of these polypeptides and of VP7, the second viral surface protein, with several cell surface molecules, including integrin αvβ3. We characterized the effect of the trypsin cleavage of VP4 on the binding to MA104 cells of the sialic acid-dependent virus strain RRV and its sialic acid-independent variant, nar3. We found that, although the trypsin treatment did not affect the attachment of these viruses to the cell surface, their binding was qualitatively different. In contrast to the trypsin-treated viruses, which initially bound to the cell surface through VP4, the non-trypsin-treated variant nar3 bound to the cell through VP7. Amino acid sequence comparison of the surface proteins of rotavirus and hantavirus, both of which interact with integrin αvβ3 in an RGD-independent manner, identified a region shared by rotavirus VP7 and hantavirus G1G2 protein in which six of nine amino acids are identical. This region, which is highly conserved among the VP7 proteins of different rotavirus strains, mediates the binding of rotaviruses to integrin αvβ3 and probably represents a novel binding motif for this integrin.

scholarly journals Cell surface acetylcholinesterase molecules on multinucleated myotubes are clustered over the nucleus of origin.

1992 ◽  
Vol 119 (6) ◽  
pp. 1657-1667 ◽  
Author(s):  
S G Rossi ◽  
R L Rotundo
Keyword(s):  
Cell Surface ◽  
Surface Membrane ◽  
Muscle Fibers ◽  
Surface Proteins ◽  
Specific Monoclonal Antibody ◽  
Hoechst 33342 ◽  
Cell Surface Proteins ◽  
Mouse Muscle ◽  
Surface Domains ◽  
Multinucleated Myotubes

Multinucleated skeletal muscle fibers are compartmentalized with respect to the expression and organization of several intracellular and cell surface proteins including acetylcholinesterase (AChE). Mosaic muscle fibers formed from homozygous myoblasts expressing two allelic variants of AChE preferentially translate and assemble the polypeptides in the vicinity of the nucleus encoding the mRNA (Rotundo, R. L. 1990. J. Cell Biol. 110:715-719). To determine whether the locally synthesized AChE molecules are targeted to specific regions of the myotube surface, primary quail myoblasts were mixed with mononucleated cells of the mouse muscle C2/C12 cell line and allowed to fuse, forming heterospecific mosaic myotubes. Cell surface enzyme was localized by immunofluorescence using an avian AChE-specific monoclonal antibody. HOECHST 33342 was used to distinguish between quail and mouse nuclei in myotubes. Over 80% of the quail nuclei exhibited clusters of cell surface AChE in mosaic quail-mouse myotubes, whereas only 4% of the mouse nuclei had adjacent quail AChE-positive regions of membrane, all of which were located next to a quail nucleus. In contrast, membrane proteins such as Na+/K+ ATPase, which are not restricted to specific regions of the myotube surface, are free to diffuse over the entire length of the fiber. These studies indicate that the AChE molecules expressed in multinucleated muscle fibers are preferentially transported and localized to regions of surface membrane overlying the nucleus of origin. This targeting could play an important role in establishing and maintaining specialized cell surface domains such as the neuromuscular and myotendinous junctions.

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