Laminins promote the locomotion of skeletal myoblasts via the alpha 7 integrin receptor

1996 ◽  
Vol 109 (13) ◽  
pp. 3139-3150 ◽  
Author(s):  
C.C. Yao ◽  
B.L. Ziober ◽  
A.E. Sutherland ◽  
D.L. Mendrick ◽  
R.H. Kramer
Keyword(s):  
Cytoplasmic Domain ◽  
Matrix Assembly ◽  
Developmentally Regulated ◽  
Laminin 5 ◽  
Alternative Mrna Splicing ◽  
Beta 1 Integrin ◽  
Alpha 7 ◽  
Myoblast Cell ◽  
And Migration

The alpha 7 beta 1 integrin is specifically expressed by skeletal and cardiac muscles, and its expression and alternative mRNA splicing at the cytoplasmic domain are developmentally regulated. We analyzed the role of alpha 7 integrin in mediating myoblast adhesion and motility on different laminin isoforms. Mouse C2C12 and MM14 myoblast cell lines were found by flow cytometry and immunoprecipitation to express high levels of the alpha 7 integrin. Overall expression of alpha 7 increased as the C2C12 myoblasts differentiated; myoblasts expressed only the alpha 7B cytoplasmic variant whereas in differentiating myotubes alpha 7A increased markedly. Function-perturbing monoclonal antibodies generated to alpha 7 integrin efficiently blocked both adhesion and migration of MM14 and C2C12 mouse myoblasts on laminin 1. Other studies with MM14 myoblasts showed that alpha 7 is also a receptor for laminin 2/4 (human placental merosins) but not for epithelial-cell-specific laminin 5. Blocking antibody to alpha 7 only partially inhibited adhesion to laminin 2/4 but almost completely blocked motility on this substrate. Finally, to assess the potential role of the alpha 7 cytoplasmic domain, CHO cells were stably transfected to expressed chimeric alpha 5 cDNA constructs containing the wild-type alpha 5 or the alpha 7A or alpha 7B cytoplasmic domain; all forms of the integrin showed identical activities for adhesion, migration, proliferation, and matrix assembly on fibronectin substrates. These results established that alpha 7 beta 1 receptor can promote myoblast adhesion and motility on a restricted number of laminin isoforms and may be important in myogenic precursor recruitment during regeneration and differentiation.

Alpha 7 beta 1 integrin is a component of the myotendinous junction on skeletal muscle

1993 ◽  
Vol 106 (2) ◽  
pp. 579-589 ◽  
Author(s):  
Z.Z. Bao ◽  
M. Lakonishok ◽  
S. Kaufman ◽  
A.F. Horwitz
Keyword(s):  
Skeletal Muscle ◽  
Cytoplasmic Domain ◽  
Cross Reactivity ◽  
Myotendinous Junction ◽  
Integrin Subunit ◽  
Adult Skeletal Muscle ◽  
Beta 1 Integrin ◽  
Alpha 7 ◽  
Adhesion Plaque

Immunization against a 70 kDa band that co-purifies with skeletal muscle integrins has resulted in an antibody directed against the avain alpha 7 integrin subunit. The specificity of the antibody was established by patterns of tissue staining and cross-reactivity with antibodies directed against the cytoplasmic domain of the rat alpha 7 cytoplasmic domain. On sections of adult skeletal muscle the alpha 7 integrin was enriched in the myotendinous junction (MTJ). This localization was unique as neither the alpha 1, alpha 3, alpha 5, alpha 6 and alpha v subunit localizes in the myotendinous junction. The distribution of the alpha 7 subunit in the MTJ was examined during embryonic development. alpha 7 expression in the junction is first apparent around embryo day 14 and is almost exclusively at the developing MTJ at this stage. alpha 3 is expressed with distinctive punctate staining around the junctional area in earlier embryos (11-day). The time of appearance of the alpha 7 subunit in the MTJ correlates with the insertion of myofibrils into subsarcolemmal densities and folding of the junctional membrane, suggesting a role of the alpha 7 integrin in this process. Vinculin is present throughout development of the myotendinous junction, suggesting that the alpha 7 integrin recognizes a preformed cytoskeletal structure. The presence of the alpha 7 subunit in the myotendinous junction and the alpha 5 subunit in the adhesion plaque demonstrates a molecular difference between these two adherens junctions. It also points to possible origins of junctional specificity on muscle. Differences between these two junctions were developed further using an antibody against phosphotyrosine (PY20). Phosphotyrosine is thought to participate in the organization and stabilization of adhesions. The focal adhesion and the neuromuscular junction, but not the MTJ, contained proteins phosphorylated on tyrosine.

scholarly journals The laminin-binding activity of the alpha 7 integrin receptor is defined by developmentally regulated splicing in the extracellular domain.

1997 ◽  
Vol 8 (9) ◽  
pp. 1723-1734 ◽  
Author(s):  
B L Ziober ◽  
Y Chen ◽  
R H Kramer
Keyword(s):  
Muscle Development ◽  
Variable Region ◽  
Extracellular Domain ◽  
Binding Activity ◽  
Developmentally Regulated ◽  
Dependent Cell ◽  
Beta 1 Integrin ◽  
Alpha 7 ◽  
A Site ◽  
Laminin Binding

The expression pattern of the laminin-binding alpha 7 beta 1 integrin is developmentally regulated in skeletal, cardiac, and smooth muscle. The X1/X2 alternative splicing in the extracellular domain of alpha 7 is found in the variable region between conserved alpha-chain homology repeat domains III and IV, a site implicated in ligand binding. To assess differences in X1/X2 isoform activity, we generated MCF-7 cell lines transfected with alpha 7-X1/X2 cDNAs. Transfectants expressing the alpha 7-X2 variant adhered rapidly to laminin 1, whereas those expressing alpha 7-X1 failed to attach. That alpha 7-X1 exists in an inactive state was established in assays using an activating beta 1 antibody that induced X1-dependent cell adhesion and spreading. Furthermore, the activation of alpha 7-X1 was cell type specific, and when expressed in HT1080 cells, the integrin was converted into a fully functional receptor capable of promoting adhesion. Thus, the expression of the alpha 7-X1/X2 integrin is a novel mechanism that regulates receptor affinity states in a cell-specific context and may modulate integrin-dependent events during muscle development and repair.

scholarly journals Regulation of cellular interactions with laminin by integrin cytoplasmic domains: the A and B structural variants of the alpha 6 beta 1 integrin differentially modulate the adhesive strength, morphology, and migration of macrophages.

1994 ◽  
Vol 5 (6) ◽  
pp. 679-690 ◽  
Author(s):  
L M Shaw ◽  
A M Mercurio
Keyword(s):  
Culture Medium ◽  
Cytoplasmic Domain ◽  
Laminin Receptor ◽  
Cellular Interactions ◽  
Structural Variants ◽  
Cytoplasmic Domains ◽  
Macrophage Cell ◽  
Beta 1 Integrin ◽  
And Migration ◽  
Migration Of Macrophages

Several integrin alpha subunits have structural variants that are identical in their extracellular and transmembrane domains but that differ in their cytoplasmic domains. The functional significance of these variants, however, is unknown. In the present study, we examined the possibility that the A and B variants of the alpha 6 beta 1 integrin laminin receptor differ in function. For this purpose, we expressed the alpha 6A and alpha 6B cDNAs, as well as a truncated alpha 6 cDNA (alpha 6-delta CYT) in which the cytoplasmic domain sequence was deleted after the GFFKR pentapeptide, in P388D1 cells, an alpha 6 deficient macrophage cell line. Populations of stable alpha 6A, alpha 6B, and alpha 6-delta CYT transfectants that expressed equivalent levels of cell surface alpha 6 were obtained by fluorescence-activated cell sorter and shown to form heterodimers with endogenous beta 1 subunits. Upon attachment to laminin, the alpha 6A transfectants extended numerous pseudopodia. In contrast, the alpha 6B transfectants remained rounded and extended few processes. The transfectants were also examined for their ability to migrate toward a laminin substratum using Transwell chambers. The alpha 6A transfectants were three- to fourfold more migratory than the alpha 6B transfectants. The alpha 6-delta CYT transfectants did not attach to laminin in normal culture medium, but they did attach in the presence of Mn2+. The alpha 6-delta CYT transfectants migrated to a lesser extent than either the alpha 6A or alpha 6B transfectants in the presence of Mn2+. The alpha 6 transfectants differed significantly in the concentration of substratum bound laminin required for half-maximal adhesion in the presence of Mn2+:alpha 6A (2.1 micrograms/ml), alpha 6B (6.3 micrograms/ml), and alpha 6-delta CYT (8.8 micrograms/ml). Divalent cation titration studies revealed that these transfectants also differed significantly in both the [Ca2+] and [Mn2+] required to obtain half-maximal adhesion to laminin. These data demonstrate that the A and B variants of the alpha 6 cytoplasmic domain can differentially modulate the function of the alpha 6 beta 1 extracellular domain.

A novel role for alpha 3 beta 1 integrins in extracellular matrix assembly

1995 ◽  
Vol 108 (6) ◽  
pp. 2511-2523 ◽  
Author(s):  
C. Wu ◽  
A.E. Chung ◽  
J.A. McDonald
Keyword(s):  
Extracellular Matrix ◽  
Cell Adhesion ◽  
Binding Activity ◽  
Integrin Subunit ◽  
Pericellular Matrix ◽  
Matrix Assembly ◽  
Amino Terminal ◽  
Beta 1 Integrin ◽  
Fibronectin Deposition

To study the biological role of alpha 3 beta 1 integrins in cell adhesion, migration, and in the deposition of extracellular matrix, we stably expressed the human alpha 3 integrin subunit in the alpha 4, alpha 5 integrin deficient CHO cell line B2. The expression of alpha 3 beta 1 integrins enhanced cell adhesion on entactin (also known as nidogen), but not on fibronectin. Using recombinant GST-fusion proteins that span the entire length of the entactin molecule, we located cell adhesive activity to the G2 domain of entactin. These results suggest that the alpha 3 beta 1 integrin functions as an adhesion receptor interacting with the G2 domain of entactin. On the other hand, the expression of alpha 3 beta 1 integrins did not confer the ability to migrate on entactin. Strikingly, the expression of alpha 3 beta 1 dramatically increased the deposition of entactin and fibronectin into the pericellular matrix. This was accompanied by increased binding activity of the 29 kDa amino-terminal domain of fibronectin. Thus, similar to alpha 5 beta 1 integrins, alpha 3 beta 1 integrins can play an important role in modulating the assembly of pericellular matrices. However, unlike fibronectin deposition supported by alpha 5 beta 1, alpha 3 beta 1 supported fibronectin deposition into pericellular matrix was not inhibited by antibodies binding to the RGD containing cell adhesion domain of fibronectin, demonstrating that the two processes are mechanistically distinct. The role of alpha 3 beta 1 in pericellular matrix assembly potentially implicates this receptor in the assembly and/or recognition of entactin-containing pericellular matrices, an observation consistent with its apparent role in the renal glomerulus of the mammalian kidney.

scholarly journals Regulation of alpha 6 beta 1 integrin laminin receptor function by the cytoplasmic domain of the alpha 6 subunit.

1993 ◽  
Vol 123 (4) ◽  
pp. 1017-1025 ◽  
Author(s):  
L M Shaw ◽  
A M Mercurio
Keyword(s):  
Point Mutations ◽  
Surface Expression ◽  
Cytoplasmic Domain ◽  
Serine Phosphorylation ◽  
Laminin Receptor ◽  
Site Directed Mutagenesis ◽  
Receptor Function ◽  
Serine Residue ◽  
Beta 1 Integrin

The alpha 6 beta 1 integrin is expressed on the macrophage surface in an inactive state and requires cellular activation with PMA or cytokines to function as a laminin receptor (Shaw, L. M., J. M. Messier, and A. M. Mercurio. 1990. J. Cell Biol. 110:2167-2174). In the present study, the role of the alpha 6 subunit cytoplasmic domain in alpha 6 beta 1 integrin activation was examined. The use of P388D1 cells, an alpha 6-integrin deficient macrophage cell line, facilitated this analysis because expression of either the alpha 6A or alpha 6B subunit cDNAs restores their activation responsive laminin adhesion (Shaw, L. S., M. Lotz, and A. M. Mercurio. 1993. J. Biol. Chem. 268:11401-11408). A truncated alpha 6 cDNA, alpha 6-delta CYT, was constructed in which the human cytoplasmic domain sequence was deleted after the GFFKR pentapeptide. Expression of this cDNA in P388D1 cells resulted in the surface expression of a chimeric alpha 6-delta CYT beta 1 integrin that was unable to mediate laminin adhesion or increase this adhesion in response to PMA under normal conditions, i.e., in medium that contained physiological concentrations of Ca++ and Mg++. The alpha 6A-delta CYT transfectants adhered to laminin, however, when Ca++/Mg++ was replaced with 150 microM Mn++. We also assessed the role of serine phosphorylation in the regulation of alpha 6A beta 1 integrin function by site-directed mutagenesis of the two serine residues present in the alpha 6A cytoplasmic domain because this domain is phosphorylated on serine residues in response to stimuli that activate the laminin receptor function of alpha 6 A beta 1. Point mutations were introduced in the alpha 6A cDNA that changed either serine residue #1064 (M1) or serine residue #1071 (M2) to alanine residues. In addition, a double mutant (M3) was constructed in which both serine residues were changed to alanine residues. P388D1 transfectants which expressed these serine mutations adhered to laminin in response to PMA to the same extent as cells transfected with wild-type alpha 6A cDNA. These findings provide evidence for a novel mode of integrin regulation that is distinct from that reported for other regulated integrins (O'Toole, T. E., D. Mandelman, J. Forsyth, S. J. Shattil, E. F. Plow, and M. H. Ginsberg. 1991. Science (Wash. DC). 254:845-847. Hibbs, M. L., H. Xu, S. A. Stacker, and T. A. Springer. 1991. Science (Wash. DC). 251:1611-1613), and they demonstrate that serine phosphorylation of the alpha 6A cytoplasmic domain is not involved in this regulation.

scholarly journals The interaction of Gα13 with integrin β1 mediates cell migration by dynamic regulation of RhoA

2015 ◽  
Vol 26 (20) ◽  
pp. 3658-3670 ◽  
Author(s):  
Bo Shen ◽  
Brian Estevez ◽  
Zheng Xu ◽  
Barry Kreutz ◽  
Andrei Karginov ◽  
...  
Keyword(s):  
Cell Migration ◽  
G Protein ◽  
Critical Role ◽  
Direct Interaction ◽  
Cytoplasmic Domain ◽  
Dynamic Regulation ◽  
Rhoa Activity ◽  
Dependent Cell ◽  
And Migration

Heterotrimeric G protein Gα13 is known to transmit G protein–coupled receptor (GPCR) signals leading to activation of RhoA and plays a role in cell migration. The mechanism underlying the role of Gα13 in cell migration, however, remains unclear. Recently we found that Gα13 interacts with the cytoplasmic domain of integrin β3 subunits in platelets via a conserved ExE motif. Here we show that a similar direct interaction between Gα13 and the cytoplasmic domain of the integrin β1 subunit plays a critical role in β1-dependent cell migration. Point mutation of either glutamic acid in the Gα13-binding 767EKE motif in β1 or treatment with a peptide derived from the Gα13-binding sequence of β1 abolished Gα13–β1 interaction and inhibited β1 integrin–dependent cell spreading and migration. We further show that the Gα13-β1 interaction mediates β1 integrin–dependent Src activation and transient RhoA inhibition during initial cell adhesion, which is in contrast to the role of Gα13 in mediating GPCR-dependent RhoA activation. These data indicate that Gα13 plays dynamic roles in both stimulating RhoA via a GPCR pathway and inhibiting RhoA via an integrin signaling pathway. This dynamic regulation of RhoA activity is critical for cell migration on β1 integrin ligands.

Control of morphology, cytoskeleton and migration by syndecan-4

1999 ◽  
Vol 112 (20) ◽  
pp. 3421-3431 ◽  
Author(s):  
R.L. Longley ◽  
A. Woods ◽  
A. Fleetwood ◽  
G.J. Cowling ◽  
J.T. Gallagher ◽  
...  
Keyword(s):  
Focal Adhesion ◽  
Core Protein ◽  
Adhesion Formation ◽  
Focal Adhesions ◽  
Cytoplasmic Domain ◽  
Fiber Formation ◽  
Microfilament Bundle ◽  
Focal Adhesion Formation ◽  
And Migration

Syndecan-4 is a widely expressed transmembrane heparan sulfate proteoglycan which localizes to focal adhesions. Previous studies showed that the syndecan-4 cytoplasmic domain can associate with and potentiate the activity of protein kinase C, which is required for focal adhesion formation. To examine further the role of syndecan-4 in cell adhesion, we expressed syndecan-4 cDNA constructs in CHO-K1 cells. Syndecan-2 transfection was used to confirm effects seen were specific for syndecan-4. Cells overexpressing full length syndecan-4 core protein exhibited a more flattened, fibroblastic morphology, with increased focal adhesion formation and decreased cell motility. Expression of a syndecan-4 core protein with either a partial or complete deletion of the cytoplasmic domain or of an antisense construct led to markedly decreased spreading and focal adhesion formation, a more epithelioid morphology, and decreased motility. Overexpression of syndecan-2 changed the adhesive phenotype, but did not markedly alter focal adhesion and microfilament bundle formation. The data suggest that syndecan-4 is a regulator of focal adhesion and stress fiber formation, and influences both morphology and migration.

Credit constraints and Rural Migration: Evidence from Six Villages in Uttar Pradesh

2018 ◽  
Vol 15 (3) ◽  
pp. 389-398
Author(s):  
Ruchi Singh
Keyword(s):  
Credit Constraints ◽  
Uttar Pradesh ◽  
Binary Logistic Regression ◽  
Binary Logistic Regression Model ◽  
Male Migration ◽  
Rural Economies ◽  
And Migration ◽  
The Relationship ◽  
The Empirical Analysis

Rural economies in developing countries are often characterized by credit constraints. Although few attempts have been made to understand the trends and patterns of male out-migration from Uttar Pradesh (UP), there is dearth of literature on the linkage between credit accessibility and male migration in rural Uttar Pradesh. The present study tries to fill this gap. The objective of this study is to assess the role of credit accessibility in determining rural male migration. A primary survey of 370 households was conducted in six villages of Jaunpur district in Uttar Pradesh. Simple statistical tools and a binary logistic regression model were used for analyzing the data. The result of the empirical analysis shows that various sources of credit and accessibility to them play a very important role in male migration in rural Uttar Pradesh. The study also found that the relationship between credit constraints and migration varies across various social groups in UP.

Role of microenvironment on proliferation and migration of an SDHB silenced murine Pheochromocytoma cell line

2017 ◽  
Author(s):  
Serena Martinelli ◽  
Vanessa D'Antongiovanni ◽  
Susan Richter ◽  
Letizia Canu ◽  
Tonino Ercolino ◽  
...  
Keyword(s):  
Cell Line ◽  
Pheochromocytoma Cell ◽  
And Migration ◽  
Proliferation And Migration
Sign in / Sign up

Export Citation Format

Share Document