Sequence and tissue distribution of the human integrin alpha 8 subunit: a beta 1-associated alpha subunit expressed in smooth muscle cells.
Integrins are a major family of cell adhesion molecules involved in cell-cell and cell-extracellular matrix interactions. Each integrin is a heterodimeric glycoprotein composed of an alpha and a beta subunit. We now report the cDNA sequence and distribution of a new human integrin alpha subunit. This sequence is 78% identical to the previously reported chicken alpha 8 integrin sequence. Thus, we have designated this subunit as human alpha 8. By northern blot analysis, an alpha 8 probe detects two mRNA species of approximately 6.5 and 4.0 kb in neuroglioma H4 cells. An anti-alpha 8 polyclonal antibody precipitates a protein complex containing the beta 1 subunit associated with the putative alpha 8 subunit, which has an apparent molecular mass of 180 kDa (non-reduced) or 155 kDa and 25 kDa (reduced). Immunohistochemistry with anti-alpha 8 polyclonal antibody in adult rat tissues shows prominent staining in vascular and visceral smooth muscle. In addition, the antibody strongly stained kidney mesangial cells and a cell type in the alveolar wall of the lungs, most likely corresponding to alveolar myofibroblasts. These results suggest that in adult mammalian tissues, alpha 8 is predominantly expressed in smooth muscle and smooth muscle-like contractile cells.
Schnapp
L M
LM
Department of Medicine, University of California at San Francisco 94143, USA.
Breuss
J M
JM
Ramos
D M
DM
Sheppard
D
D
Pytela
R
R
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D002460:Cell Line; D002645:Chickens; D003001:Cloning, Molecular; D018076:DNA, Complementary; D006801:Humans; D007150:Immunohistochemistry; D039001:Integrin alpha Chains; D016023:Integrins / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D009130:Muscle, Smooth / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D014407:Tumor Cells, Cultured
D018076:DNA, Complementary; D039001:Integrin alpha Chains; D016023:Integrins; D012333:RNA, Messenger; C093856:integrin alpha8