Integrin-linked kinase complexes with caveolin-1 in human neuroblastoma cells.
Integrin-linked kinase (ILK) and caveolin-1 (cav-1) are implicated in the pathogenesis of cancer. Overexpression of ILK leads to altered expression of cell cycle regulators, a decreased level of cell adhesion to the extracellular matrix, a decreased level of apoptosis, in vitro phosphorylation of Akt, and tumor formation in nude mice. Conversely, cav-1 expression is frequently downregulated in many forms of cancer. We examined whether ILK and cav-1 interact in SHEP human neuroblastoma cells because ILK is present in caveolae-enriched membranes and contains a putative cav-binding domain. SHEP cells were stably transfected with vector, wild-type ILK (ILK-wt), kinase-deficient ILK (ILK-kd), or mutant cav-binding domain ILK (ILK-mutCavbd). Control SHEP cells and ILK transfectants express high levels of ILK and cav-1. Immunoprecipitation with anti-cav-1 co-immunoprecipitates a 59 kDa protein that is immunoreactive with the anti-ILK antibody, and this interaction is partially prevented in cells expressing ILK-mutCavbd. Cav-1 and ILK partially colocalize in SHEP cells, also supporting these data. Last, affinity chromatography with a biotinylated cav-scaffolding domain peptide precipitates ILK-wt but not ILK-mutCavbd. These data suggest that the cav-binding domain of ILK and the cav-scaffolding domain of cav-1 mediate complex formation in human neuroblastoma cells.
Meyer
Amy
A
Department of Neurology, University of Michigan, Ann Arbor, Michigan 48109, USA.
van Golen
Cynthia M
CM
Boyanapalli
Madanamohan
M
Kim
Bhumsoo
B
Soules
Mary E
ME
Feldman
Eva L
EL
D000595:Amino Acid Sequence; D001483:Base Sequence; D051242:Caveolin 1; D022461:Caveolins / Q000378:metabolism*; D045744:Cell Line, Tumor; D017931:DNA Primers; D005455:Fluorescent Antibody Technique; D006801:Humans; D047468:Immunoprecipitation; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D000099200:Scaffold Protein ILK
D051242:Caveolin 1; D022461:Caveolins; D017931:DNA Primers; D017346:Protein Serine-Threonine Kinases; D000099200:Scaffold Protein ILK; C495540:CAV1 protein, human