title: Interaction of the immunoglobulin-like cell adhesion molecule hepaCAM with caveolin-1.
abstract: Subsequent to our identification of the novel immunoglobulin-like cell adhesion molecule hepaCAM, we demonstrated that hepaCAM is capable of modulating cell growth and cell-extracellular matrix interactions. In this study, we examined the localization of hepaCAM in lipid rafts/caveolae as well as the interaction of hepaCAM with the caveolar structural protein caveolin-1 (Cav-1). Our results revealed that a portion of hepaCAM resided in detergent-resistant membranes and co-partitioned with Cav-1 to low buoyant density fractions characteristic of lipid rafts/caveolae. In addition, co-localization and coimmunoprecipitation assays confirmed the association of hepaCAM with Cav-1. Deletion analysis of hepaCAM showed that the extracellular first immunoglobulin domain of hepaCAM was required for binding Cav-1. Furthermore, when co-expressed, Cav-1 induced the expression of hepaCAM as well as distributed hepaCAM to intracellular Cav-1-positive caveolar structures. Taken together, our findings indicate that hepaCAM is partially localized in the lipid rafts/caveolae and interacts with Cav-1 through its first immunoglobulin domain.
authors.affiliation: Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
authors.forename: Mei Chung
authors.initials: MC
authors.lastname: Moh
authors.forename: Lay Hoon
authors.initials: LH
authors.lastname: Lee
authors.forename: Ting
authors.initials: T
authors.lastname: Zhang
authors.forename: Shali
authors.initials: S
authors.lastname: Shen
mesh_terms: D000818:Animals; D021941:Caveolae / Q000378:metabolism*; D051242:Caveolin 1 / Q000378:metabolism*; D015815:Cell Adhesion Molecules / Q000378:metabolism*; D018797:Cell Cycle Proteins; D045744:Cell Line, Tumor; D006801:Humans; D007136:Immunoglobulins / Q000737:chemistry; D051379:Mice; D041681:NIH 3T3 Cells; D025941:Protein Interaction Mapping; D017434:Protein Structure, Tertiary; D011506:Proteins / Q000235:genetics / Q000378:metabolism*; D017384:Sequence Deletion; D015398:Signal Transduction
chemical_list: D051242:Caveolin 1; D015815:Cell Adhesion Molecules; D018797:Cell Cycle Proteins; C487620:HEPACAM protein, human; D007136:Immunoglobulins; D011506:Proteins