Integrin function: molecular hierarchies of cytoskeletal and signaling molecules

Integrin receptors play important roles in organizing the actin- containing cytoskeleton and in signal transduction from the extracellular matrix. The initial steps in integrin function can be analyzed experimentally using beads coated with ligands or anti- integrin antibodies to trigger rapid focal transmembrane responses. A hierarchy of transmembrane actions was identified in this study. Simple integrin aggregation triggered localized transmembrane accumulation of 20 signal transduction molecules, including RhoA, Rac1, Ras, Raf, MEK, ERK, and JNK. In contrast, out of eight cytoskeletal molecules tested, only tensin coaccumulated. Integrin aggregation alone was also sufficient to induce rapid activation of the JNK pathway, with kinetics of activation different from those of ERK. The tyrosine kinase inhibitors herbimycin A or genistein blocked both the accumulation of 19 out of 20 signal transduction molecules and JNK- and ERK-mediated signaling. Cytochalasin D had identical effects, whereas three other tyrosine kinase inhibitors did not. The sole exception among signaling molecules was the kinase pp125FAK which continued to coaggregate with alpha 5 beta 1 integrins even in the presence of these inhibitors. Tyrosine kinase inhibition also failed to block the ability of ligand occupancy plus integrin aggregation to trigger transmembrane accumulation of the three cytoskeletal molecules talin, alpha-actinin, and vinculin; these molecules accumulated even in the presence of cytochalasin D. However, it was necessary to fulfill all four conditions, i.e., integrin aggregation, integrin occupancy, tyrosine kinase activity, and actin cytoskeletal integrity, to achieve integrin- mediated focal accumulation of other cytoskeletal molecules including F- actin and paxillin. Integrins therefore mediate a transmembrane hierarchy of molecular responses.

[1]  M. Humphries,et al.  Identification of two distinct regions of the type III connecting segment of human plasma fibronectin that promote cell type-specific adhesion. , 1987, The Journal of biological chemistry.

[2]  M. Karin,et al.  NF-kappa B activation by ultraviolet light not dependent on a nuclear signal. , 1993, Science.

[3]  R L Juliano,et al.  Signal transduction by integrins: increased protein tyrosine phosphorylation caused by clustering of beta 1 integrins. , 1991, Proceedings of the National Academy of Sciences of the United States of America.

[4]  J. Woodgett,et al.  Transforming G Protein-coupled Receptors Potently Activate JNK (SAPK) , 1995, The Journal of Biological Chemistry.

[5]  G L Johnson,et al.  Differential activation of ERK and JNK mitogen-activated protein kinases by Raf-1 and MEKK. , 1994, Science.

[6]  J. Parsons,et al.  Identification and characterization of novel substrates for protein tyrosine kinases. , 1993, Progress in nucleic acid research and molecular biology.

[7]  B. Geiger,et al.  Interaction of fibronectin-coated beads with attached and spread fibroblasts. Binding, phagocytosis, and cytoskeletal reorganization. , 1986, Experimental cell research.

[8]  J. Brugge,et al.  Adhesive signaling in platelets. , 1994, Current opinion in cell biology.

[9]  Kenneth M. Yamada,et al.  Regulation of fibronectin receptor distribution [published erratum appears in J Cell Biol 1992 Jul;118(2):491] , 1992, The Journal of cell biology.

[10]  C. Lechene,et al.  Insoluble fibronectin activates the Na/H antiporter by clustering and immobilizing integrin alpha 5 beta 1, independent of cell shape. , 1991, Proceedings of the National Academy of Sciences of the United States of America.

[11]  J. Brugge,et al.  Integrins and signal transduction pathways: the road taken. , 1995, Science.

[12]  H. Gralnick,et al.  Novel function for beta 1 integrins in keratinocyte cell-cell interactions , 1990, The Journal of cell biology.

[13]  M. Schwartz,et al.  Mapping in vivo associations of cytoplasmic proteins with integrin beta 1 cytoplasmic domain mutants. , 1995, Molecular biology of the cell.

[14]  L. Zon,et al.  Role of SAPK/ERK kinase-1 in the stress-activated pathway regulating transcription factor c-Jun , 1994, Nature.

[15]  F. Cross,et al.  Signal transduction in the budding yeast Saccharomyces cerevisiae. , 1994, Current opinion in cell biology.

[16]  K. Burridge,et al.  An Interaction between a-Actinin and the/ 1 Integrin Subunit In Vitro , 1990 .

[17]  B. Gumbiner,et al.  Proteins associated with with cytoplasmic surface of adhesion molecules , 1993, Neuron.

[18]  M. Karin,et al.  JNK1: A protein kinase stimulated by UV light and Ha-Ras that binds and phosphorylates the c-Jun activation domain , 1994, Cell.

[19]  M. Beckerle,et al.  Interaction of plasma membrane fibronectin receptor with talin—a transmembrane linkage , 1986, Nature.

[20]  C. Turner,et al.  Focal adhesions: transmembrane junctions between the extracellular matrix and the cytoskeleton. , 1988, Annual review of cell biology.

[21]  M. Schwartz,et al.  Integrin beta 1- and beta 3-mediated endothelial cell migration is triggered through distinct signaling mechanisms , 1993, The Journal of cell biology.

[22]  W. T. Chen,et al.  Dynamic cytoskeleton-integrin associations induced by cell binding to immobilized fibronectin , 1989, The Journal of cell biology.

[23]  Kenneth M. Yamada,et al.  Synergistic roles for receptor occupancy and aggregation in integrin transmembrane function , 1995, Science.

[24]  R. Davis,et al.  MAPKs: new JNK expands the group. , 1994, Trends in biochemical sciences.

[25]  K. Yamada,et al.  Transmembrane signal transduction by integrin cytoplasmic domains expressed in single-subunit chimeras. , 1994, The Journal of biological chemistry.

[26]  C. Ostberg,et al.  Fibronectin attachment activates the NF-kappa B p50/p65 heterodimer in fibroblasts and smooth muscle cells. , 1994, The Journal of biological chemistry.

[27]  J. Parsons,et al.  Focal adhesion kinase and associated proteins. , 1994, Current opinion in cell biology.

[28]  M. Shibuya,et al.  Genistein, a specific inhibitor of tyrosine-specific protein kinases. , 1987, The Journal of biological chemistry.

[29]  G. Plopper,et al.  Rapid induction and isolation of focal adhesion complexes. , 1993, Biochemical and biophysical research communications.

[30]  T. Hunter,et al.  Integrin-mediated signal transduction linked to Ras pathway by GRB2 binding to focal adhesion kinase , 1994, Nature.

[31]  M. Kinch,et al.  Integrin-mediated cell adhesion activates mitogen-activated protein kinases. , 1994, The Journal of biological chemistry.

[32]  J. Parsons,et al.  pp125FAK a structurally distinctive protein-tyrosine kinase associated with focal adhesions. , 1992, Proceedings of the National Academy of Sciences of the United States of America.

[33]  L. Zon,et al.  Activation of stress-activated protein kinase by MEKK1 phosphorylation of its activator SEK1 , 1994, Nature.

[34]  Y. Yazaki,et al.  Matrix/Integrin Interaction Activates the Mitogen-activated Protein Kinase, p44 and p42(*) , 1995, The Journal of Biological Chemistry.

[35]  H Umezawa,et al.  Phenotypic change from transformed to normal induced by benzoquinonoid ansamycins accompanies inactivation of p60src in rat kidney cells infected with Rous sarcoma virus , 1986, Molecular and cellular biology.

[36]  Richard O. Hynes,et al.  Integrins: Versatility, modulation, and signaling in cell adhesion , 1992, Cell.

[37]  J. Brugge,et al.  Adhesive ligand binding to integrin alpha IIb beta 3 stimulates tyrosine phosphorylation of novel protein substrates before phosphorylation of pp125FAK , 1993, The Journal of cell biology.

[38]  W. T. Chen,et al.  Analysis of fibronectin receptor function with monoclonal antibodies: roles in cell adhesion, migration, matrix assembly, and cytoskeletal organization , 1989, The Journal of cell biology.

[39]  C. Otey,et al.  Role of Adhesion Molecule Cytoplasmic Domains in Mediating Interactions with the Cytoskeleton , 1994, Proceedings of the Society for Experimental Biology and Medicine. Society for Experimental Biology and Medicine.

[40]  A. Levitzki,et al.  Tyrphostins--potential antiproliferative agents and novel molecular tools. , 1990, Biochemical pharmacology.

[41]  A. Horwitz,et al.  Integrin cytoplasmic domains: mediators of cytoskeletal linkages and extra- and intracellular initiated transmembrane signaling. , 1993, Current opinion in cell biology.

[42]  J. Parsons,et al.  Tyrosine phosphorylation of pp125FAK in platelets requires coordinated signaling through integrin and agonist receptors. , 1994, The Journal of biological chemistry.

[43]  S. Haskill,et al.  Signal transduction from the extracellular matrix , 1993, The Journal of cell biology.