Functional co-localization of monocytic aminopeptidase N/CD13 with the Fc gamma receptors CD32 and CD64.
Information about the function of aminopeptidase N/CD13 on monocytes is limited. In order to gain more insight into its interaction with other proteins, we have identified molecules that co-localize with the membrane ectoenzyme at the cell surface of monocytes. Using laser scanning and electron microscopy as well as fluorescence resonance energy transfer (FRET) measured by flow cytometry we show that monocytic CD13 co-localized with the Fc gamma receptor II/CD32 after Fc receptor ligation by a CD32-specific antibody. FRET was also observed between CD13 and the Fc gamma receptor I/CD64, but not with the myeloid marker CD33 representing a member of the sialoadhesin family. Our results imply a novel functional role of CD13 and Fc gamma receptors as members of a multimeric receptor complex. Further studies have to be done to elucidate common signaling pathways of these molecules.
Riemann
Dagmar
D
Institute of Medical Immunology, Martin Luther University Halle/Wittenberg, Magdeburger Strasse 2, D-06097 Halle, Germany. dagmar.riemann@medizin.uni-halle.de
Tcherkes
Anatolij
A
Hansen
Gert H
GH
Wulfaenger
Jens
J
Blosz
Tanja
T
Danielsen
E Michael
EM
D018826:CD13 Antigens / Q000378:metabolism*; D045744:Cell Line, Tumor; D005434:Flow Cytometry; D031541:Fluorescence Resonance Energy Transfer; D006801:Humans; D008854:Microscopy, Electron; D009000:Monocytes / Q000201:enzymology*; D017452:Receptors, IgG / Q000378:metabolism*
D017452:Receptors, IgG; D018826:CD13 Antigens