Direct extracellular contact between integrin alpha(3)beta(1) and TM4SF protein CD151.
Previously we established that the alpha(3)beta(1) integrin shows stable, specific, and stoichiometric association with the TM4SF (tetraspannin) protein CD151. Here we used a membrane impermeable cross-linking agent to show a direct association between extracellular domains of alpha(3)beta(1) and CD151. The alpha(3)beta(1)-CD151 association site was then mapped using chimeric alpha(6)/alpha(3) integrins and CD151/NAG2 TM4SF proteins. Complex formation required an extracellular alpha(3) site (amino acids (aa) 570-705) not previously known to be involved in specific integrin contacts with other proteins and a region (aa 186-217) within the large extracellular loop of CD151. Notably, the anti-CD151 monoclonal antibody TS151r binding epitope, previously implicated in alpha(3) integrin association, was mapped to the same region of CD151 (aa 186-217). Finally, we demonstrated that both NH(2)- and COOH-terminal domains of CD151 are located on the inside of the plasma membrane, thus confirming a long suspected model of TM4SF protein topology.
Yauch
R L
RL
Department of Cancer Immunology and AIDS, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts 02115, USA.
Kazarov
A R
AR
Desai
B
B
Lee
R T
RT
Hemler
M E
ME
D000595:Amino Acid Sequence; D000818:Animals; D015703:Antigens, CD / Q000737:chemistry / Q000378:metabolism*; D001483:Base Sequence; D002460:Cell Line; D005110:Extracellular Space; D006801:Humans; D039201:Integrin alpha3beta1; D016023:Integrins / Q000378:metabolism*; D008969:Molecular Sequence Data; D011485:Protein Binding; D011487:Protein Conformation; D060185:Tetraspanin 24
D015703:Antigens, CD; C554715:CD151 protein, human; D039201:Integrin alpha3beta1; D016023:Integrins; D060185:Tetraspanin 24