TY - JOUR

T1 - Hierarchy of ADAM12 binding to integrins in tumor cells.

AU - Thodeti, Charles Kumar

AU - Fröhlich, Camilla

AU - Nielsen, Christian Kamp

AU - Holck, Peter

AU - Sundberg, Christina

AU - Kveiborg, Marie

AU - Mahalingam, Yashithra

AU - Albrechtsen, Reidar

AU - Couchman, John R

AU - Wewer, Ulla M

N1 - Keywords: 1-Phosphatidylinositol 3-Kinase; ADAM Proteins; Animals; CHO Cells; Cell Adhesion; Cell Line, Tumor; Cell Movement; Cells, Cultured; Cricetinae; Cricetulus; Dogs; Humans; Integrins; Membrane Proteins; Metalloendopeptidases; Protein Structure, Tertiary; Rats

PY - 2005

Y1 - 2005

N2 - ADAMs (a disintegrin and metalloprotease) comprise a family of cell surface proteins with protease and cell-binding activities. Using different forms and fragments of ADAM12 as substrates in cell adhesion and spreading assays, we demonstrated that alpha9beta1 integrin is the main receptor for ADAM12. However, when alpha9beta1 integrin is not expressed--as in many carcinoma cells--other members of the beta1 integrin family can replace its ligand binding activity. In attachment assays, the recombinant disintegrin domain of ADAM12 only supported alpha9 integrin-dependent tumor cell attachment, whereas full-length ADAM12 supported attachment via alpha9 integrin and other integrin receptors. Cells that attached to full-length ADAM12 in an alpha9 integrin-dependent manner also attached to ADAM12 in which the putative alpha9beta1 integrin-binding motif in the disintegrin domain had been mutated. This attachment was mediated through use of an alternate beta1 integrin. We also found that cell spreading in response to ADAM12 is dependent on the apparent level of integrin activation. Binding of cells to ADAM12 via the alpha9beta1 integrin was Mn(2+)-independent and resulted in attachment of cells with a rounded morphology; attachment of cells with a spread morphology required further activation of the alpha9beta1 integrin. We demonstrated that phosphoinositide-3-kinase appears to be central in regulating alpha9beta1 integrin cell spreading activity in response to ADAM12.

AB - ADAMs (a disintegrin and metalloprotease) comprise a family of cell surface proteins with protease and cell-binding activities. Using different forms and fragments of ADAM12 as substrates in cell adhesion and spreading assays, we demonstrated that alpha9beta1 integrin is the main receptor for ADAM12. However, when alpha9beta1 integrin is not expressed--as in many carcinoma cells--other members of the beta1 integrin family can replace its ligand binding activity. In attachment assays, the recombinant disintegrin domain of ADAM12 only supported alpha9 integrin-dependent tumor cell attachment, whereas full-length ADAM12 supported attachment via alpha9 integrin and other integrin receptors. Cells that attached to full-length ADAM12 in an alpha9 integrin-dependent manner also attached to ADAM12 in which the putative alpha9beta1 integrin-binding motif in the disintegrin domain had been mutated. This attachment was mediated through use of an alternate beta1 integrin. We also found that cell spreading in response to ADAM12 is dependent on the apparent level of integrin activation. Binding of cells to ADAM12 via the alpha9beta1 integrin was Mn(2+)-independent and resulted in attachment of cells with a rounded morphology; attachment of cells with a spread morphology required further activation of the alpha9beta1 integrin. We demonstrated that phosphoinositide-3-kinase appears to be central in regulating alpha9beta1 integrin cell spreading activity in response to ADAM12.

U2 - 10.1016/j.yexcr.2005.06.020

DO - 10.1016/j.yexcr.2005.06.020

M3 - Journal article

C2 - 16061220

VL - 309

SP - 438

EP - 450

JO - Experimental Cell Research

JF - Experimental Cell Research

SN - 0014-4827

IS - 2

ER -