TY - JOUR

T1 - ADAM12/syndecan-4 signaling promotes beta 1 integrin-dependent cell spreading through protein kinase Calpha and RhoA.

AU - Thodeti, Charles Kumar

AU - Albrechtsen, Reidar

AU - Grauslund, Morten

AU - Asmar, Meena

AU - Larsson, Christer

AU - Takada, Yoshikazu

AU - Mercurio, Arthur M

AU - Couchman, John R

AU - Wewer, Ulla M

N1 - Keywords: ADAM Proteins; Amino Acid Sequence; Animals; Antibodies, Monoclonal; Antigens, CD29; CHO Cells; Cell Adhesion; Cell Movement; Cricetinae; Cysteine; DNA, Complementary; Humans; Immunohistochemistry; Membrane Proteins; Metalloendopeptidases; Microscopy, Fluorescence; Microscopy, Phase-Contrast; Models, Biological; Molecular Sequence Data; Muscle Proteins; Protein Kinase C; Protein Kinase C-alpha; Protein Structure, Tertiary; Rats; Sequence Homology, Amino Acid; Signal Transduction; Transfection; rhoA GTP-Binding Protein

PY - 2002

Y1 - 2002

N2 - The ADAMs (a disintegrin and metalloprotease) comprise a large family of multidomain proteins with cell-binding and metalloprotease activities. The ADAM12 cysteine-rich domain (rADAM12-cys) supports cell attachment using syndecan-4 as a primary cell surface receptor that subsequently triggers beta(1) integrin-dependent cell spreading, stress fiber assembly, and focal adhesion formation. This process contrasts with cell adhesion on fibronectin, which is integrin-initiated but syndecan-4-dependent. In the present study, we investigated ADAM12/syndecan-4 signaling leading to cell spreading and stress fiber formation. We demonstrate that syndecan-4, when present in significant amounts, promotes beta(1) integrin-dependent cell spreading and stress fiber formation in response to rADAM12-cys. A mutant form of syndecan-4 deficient in protein kinase C (PKC)alpha activation or a different member of the syndecan family, syndecan-2, was unable to promote cell spreading. GF109203X and Gö6976, inhibitors of PKC, completely inhibited ADAM12/syndecan-4-induced cell spreading. Expression of syndecan-4, but not syn4DeltaI, resulted in the accumulation of activated beta(1) integrins at the cell periphery in Chinese hamster ovary beta1 cells as revealed by 12G10 staining. Further, expression of myristoylated, constitutively active PKCalpha resulted in beta(1) integrin-dependent cell spreading, but additional activation of RhoA was required to induce stress fiber formation. In summary, these data provide novel insights into syndecan-4 signaling. Syndecan-4 can promote cell spreading in a beta(1) integrin-dependent fashion through PKCalpha and RhoA, and PKCalpha and RhoA likely function in separate pathways.

AB - The ADAMs (a disintegrin and metalloprotease) comprise a large family of multidomain proteins with cell-binding and metalloprotease activities. The ADAM12 cysteine-rich domain (rADAM12-cys) supports cell attachment using syndecan-4 as a primary cell surface receptor that subsequently triggers beta(1) integrin-dependent cell spreading, stress fiber assembly, and focal adhesion formation. This process contrasts with cell adhesion on fibronectin, which is integrin-initiated but syndecan-4-dependent. In the present study, we investigated ADAM12/syndecan-4 signaling leading to cell spreading and stress fiber formation. We demonstrate that syndecan-4, when present in significant amounts, promotes beta(1) integrin-dependent cell spreading and stress fiber formation in response to rADAM12-cys. A mutant form of syndecan-4 deficient in protein kinase C (PKC)alpha activation or a different member of the syndecan family, syndecan-2, was unable to promote cell spreading. GF109203X and Gö6976, inhibitors of PKC, completely inhibited ADAM12/syndecan-4-induced cell spreading. Expression of syndecan-4, but not syn4DeltaI, resulted in the accumulation of activated beta(1) integrins at the cell periphery in Chinese hamster ovary beta1 cells as revealed by 12G10 staining. Further, expression of myristoylated, constitutively active PKCalpha resulted in beta(1) integrin-dependent cell spreading, but additional activation of RhoA was required to induce stress fiber formation. In summary, these data provide novel insights into syndecan-4 signaling. Syndecan-4 can promote cell spreading in a beta(1) integrin-dependent fashion through PKCalpha and RhoA, and PKCalpha and RhoA likely function in separate pathways.

U2 - 10.1074/jbc.M208937200

DO - 10.1074/jbc.M208937200

M3 - Journal article

C2 - 12509413

VL - 278

SP - 9576

EP - 9584

JO - Journal of Biological Chemistry

JF - Journal of Biological Chemistry

SN - 0021-9258

IS - 11

ER -