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Titolo:
The role of extracellular and cytoplasmic splice domains of alpha 7-integrin in cell adhesion and migration on laminins
Autore:
Schober, S; Mielenz, D; Echtermeyer, F; Hapke, S; Poschl, E; von der Mark, H; Moch, H; von der Mark, K;
Indirizzi:
Univ Erlangen Nurnberg, Inst Expt Med, D-91054 Erlangen, Germany Univ Erlangen Nurnberg Erlangen Germany D-91054 -91054 Erlangen, Germany
Titolo Testata:
EXPERIMENTAL CELL RESEARCH
fascicolo: 2, volume: 255, anno: 2000,
pagine: 303 - 313
SICI:
0014-4827(20000315)255:2<303:TROEAC>2.0.ZU;2-#
Fonte:
ISI
Lingua:
ENG
Soggetto:
ALPHA-7 INTEGRIN RECEPTOR; SKELETAL-MUSCLE; EPITHELIAL DEVELOPMENT; MELANOMA-CELLS; EXPRESSION; MYOBLASTS; ISOFORMS; MATRIX; DISTINCT; SUBUNIT;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
55
Recensione:
Indirizzi per estratti:
Indirizzo: von der Mark, K Univ Erlangen Nurnberg, Inst Expt Med, D-91054 Erlangen, Germany Univ Erlangen Nurnberg Erlangen Germany D-91054 Germany
Citazione:
S. Schober et al., "The role of extracellular and cytoplasmic splice domains of alpha 7-integrin in cell adhesion and migration on laminins", EXP CELL RE, 255(2), 2000, pp. 303-313

Abstract

The major laminin-binding integrin of skeletal, smooth, and heart muscle is alpha 7 beta 1-integrin, which is structurally related to alpha 6 beta 1. It occurs in three cytoplasmic splice variants (alpha 7A, -B, and -C) and two extracellular forms (X1 and X2) which are developmentally regulated anddifferentially expressed in skeletal muscle. Previously, we have shown that ectopic expression of the alpha 7B-integrin splice variant in nonmotile HEK293 cells specifically induced cell locomotion on laminin-1 but not on fibronectin. To investigate the specificity and the mechanism of the alpha 7-mediated cell motility, we expressed the three alpha 7-chain cytoplasmic splice variants, as well as alpha 6A- and alpha 6B-integrin subunits in HEK293 cells. Here we show that all three alpha 7 splice variants (containing the X2 domain), as well as alpha 6A and alpha 6B, promote cell attachment andstimulate cell motility on laminin-1 and its E8 fragment. Deletion of the cytoplasmic domain (excluding the GFFKR consensus sequence) from alpha 7B resulted in a loss of the motility-enhancing effect. On laminin-2/4 (merosin), the predominant isoform in mature skeletal muscle, only alpha 7-expressing cells showed enhanced motility, whereas cells transfected with alpha 6A and alpha 6B neither attached nor migrated on laminin-2. Adhesion of alpha 7-expressing cells to both laminin-1 and laminin-2 was specifically inhibited by a new monoclonal antibody (6A11) specific for alpha 7. Expression of the two extracellular splice variants alpha 7X1 and alpha 7X2 in HEK293 cells conferred different motilities on laminin isoforms: Whereas alpha 7X2B promoted cell migration on both laminin-1 and laminin-2, alpha 7X1B supported motility only on laminin-2 and not on laminin-1, although both X1 and X2 splice variants revealed similar adhesion rates to laminin-1 and -2. Fluorescence-activated cell sorter analysis revealed a dramatic reduction of surface expression of alpha 6-integrin subunits after alpha 7A or -B trans-fection; also, surface expression of alpha 1-, alpha 3-, and alpha 5- integrinswas significantly reduced. These results demonstrate selective responses of alpha 6- and alpha 7-integrins and of the alpha 7 splice variants to laminin-1 and -2 and indicate differential roles in laminin-controlled cell adhesion and migration. (C) 2000 Academic Press.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 24/11/20 alle ore 14:39:53