Integrin-Linked Kinase Complexes with Caveolin-1 in Human Neuroblastoma Cells

• Published in: Biochemistry (Easton) Vol. 44; no. 3; pp. 932 - 938
• Main Authors: Meyer, Amy, van Golen, Cynthia M, Boyanapalli, Madanamohan, Kim, Bhumsoo, Soules, Mary E, Feldman, Eva L
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 25-01-2005
• Subjects: Amino Acid Sequence; Base Sequence; Caveolin 1; Caveolins - metabolism; Cell Line, Tumor; DNA Primers; Fluorescent Antibody Technique; Humans; Immunoprecipitation; Molecular Sequence Data; Mutagenesis, Site-Directed; Protein-Serine-Threonine Kinases - genetics; Protein-Serine-Threonine Kinases - metabolism
• ISSN: 0006-2960; 1520-4995
• DOI: 10.1021/bi048619r

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.