Fibronectin on activated T lymphocytes is bound to gangliosides and is present in detergent insoluble microdomains.
Fibronectin (FN) is a multifunctional extracellular matrix glycoprotein, which participates in cell migration and signalling to adhering cells. Due to alternative splicing and post-translational modifications, different isoforms of FN are generated by a wide variety of cells. T lymphocytes synthesize a surface-associated isoform of FN, containing the two 'extradomains' EDA and EDB. In the present study, we identified gangliosides within the T-cell membrane as specific binding sites for the N-terminal 30 kDa fragment of FN. When T cells were activated with anti-CD3 coated beads, FN, together with the ganglioside GM1, converged at the contact zone. Moreover, endogenous FN was present in the detergent insoluble microdomain. The function of FN in T cells is still under investigation; however, its presence together with gangliosides at the activation site suggests participation in T-cell signalling.
Blum
Stefan
S
Institute for Immunology, University of Heidelberg, Heidelberg, Germany.
Hug
Friederike
F
Hänsch
Gertrud M
GM
Wagner
Christof
C
D001665:Binding Sites; D005353:Fibronectins / Q000378:metabolism*; D005732:Gangliosides / Q000378:metabolism*; D006801:Humans; D008213:Lymphocyte Activation / Q000502:physiology; D021962:Membrane Microdomains / Q000378:metabolism*; D010446:Peptide Fragments / Q000378:metabolism; D013601:T-Lymphocytes / Q000276:immunology / Q000378:metabolism*
D005353:Fibronectins; D005732:Gangliosides; D010446:Peptide Fragments