Alpha7 integrin mediates cell adhesion and migration on specific laminin isoforms.
The laminin-binding alpha7beta1 integrin receptor is expressed at high levels by skeletal and cardiac muscles and by certain melanocytic cells. We have assessed the potential role of the alpha7A/B integrin isoforms in mediating cell adhesion and motility and determined the laminin isoform specificity of this integrin. When MCF-7 breast carcinoma cells, normally nonadherent to laminin 1, were stably transfected with cDNA for mouse alpha7, they adhered with high efficiency and migrated on laminin 1 substrates. Function-perturbing monoclonal antibodies generated to mouse alpha7 subunit blocked both adhesion and migration of alpha7 transfectants on laminin 1 substrates. Additional studies with MCF-7 transfectants revealed that alpha7beta1 binds well to laminin 1 and to a mixture of laminin 2 and 4 but not to laminin 5. Importantly, alpha7beta1 was capable of promoting motility on both laminin 1 and laminin 2/4 substrates. However, MCF-7 cells transfected with cDNA for either alpha7A or alpha7B showed no significant differences in cell adhesion or motility on laminin 1 substrates. Although the role for the alternatively spliced cytoplasmic variants of alpha7 remains unknown, the results establish that alpha7beta1 mediates cell adhesive activities on a restricted number of laminin isoforms.
Yao
C C
CC
Department of Stomatology, Schools of Dentistry and Medicine, University of California San Francisco, 94143-0512, USA.
Ziober
B L
BL
Squillace
R M
RM
Kramer
R H
RH
D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D015703:Antigens, CD / Q000096:biosynthesis / Q000737:chemistry / Q000502:physiology*; D001483:Base Sequence; D001943:Breast Neoplasms; D002448:Cell Adhesion; D002460:Cell Line; D002465:Cell Movement; D017931:DNA Primers; D005260:Female; D006801:Humans; D039001:Integrin alpha Chains; D016023:Integrins / Q000502:physiology; D007700:Kinetics; D007797:Laminin; D051379:Mice; D008969:Molecular Sequence Data; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D014162:Transfection
D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D017931:DNA Primers; D039001:Integrin alpha Chains; D016023:Integrins; D007797:Laminin; D011994:Recombinant Proteins; C085725:integrin alpha7; C082908:integrin alpha7beta1