| First Author | Alais S | Year | 2001 |
| Journal | J Cell Sci | Volume | 114 |
| Issue | Pt 10 | Pages | 1847-59 |
| PubMed ID | 11329371 | Mgi Jnum | J:69820 |
| Mgi Id | MGI:2135509 | Doi | 10.1242/jcs.114.10.1847 |
| Citation | Alais S, et al. (2001) HEMCAM/CD146 downregulates cell surface expression of beta1 integrins. J Cell Sci 114(Pt 10):1847-59 |
| abstractText | HEMCAM/gicerin, an immunoglobulin superfamily protein, is involved in homophilic and heterophilic adhesion. It interacts with NOF (neurite outgrowth factor), a molecule of the laminin family. Alternative splicing leads to mRNAs coding for HEMCAM with a short (HEMCAM-s) or a long cytoplasmic tail (HEMCAM-l). To investigate the cellular function of these two variants, we stably transfected murine fibroblasts with either form of HEMCAM. Expression of each isoform of this protein in L cells delayed proliferation and modified their adhesion properties to purified extracellular matrix proteins. Expression of either HEMCAM-s or HEMCAM-l inhibited integrin-dependent adhesion and spreading of fibroblasts to laminin 1, showing that this phenomenon did not depend on the cytoplasmic region. By contrast, L-cell adhesion and spreading to fibronectin depended on the HEMCAM isoform expressed. Flow cytometry and immunoprecipitation studies revealed that the expression of HEMCAM downregulated expression of the laminin-binding integrins alpha3beta1, alpha6beta1 and alpha7beta1, and fibronectin receptor alpha5beta1 from the cell surface. Semi-quantitative PCR and northern blot experiments showed that the expression of alpha6beta1 integrin modified by HEMCAM occurred at a translation or maturation level. Thus, our data demonstrate that HEMCAM regulates fibroblast adhesion by controlling beta1 integrin expression. |
