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Fluorescence correlation spectroscopy reveals topological segregation of the two tumor necrosis factor membrane receptors

Lookup NU author(s): Dr Anja Krippner-Heidenreich

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Abstract

The proinflammatory cytokine tumor necrosis factor (TNF) binds two distinct plasma membrane receptors, TNFR1 and TNFR2. We have produced different receptor mutants fused with enhanced green fluorescent protein to study their membrane dynamics by fluorescence correlation spectroscopy (FCS). TNFR1 mutants show diffusion constants of approximately 1.2 × 10^{− 9} cm²/s and a broad distribution of diffusion times, which is hardly affected by ligand binding. However, cholesterol depletion enhances their diffusion, suggesting a constitutive affinity to cholesterol rich membrane microdomains. In contrast, TNFR2 and mutants thereof diffuse rather fast (D̄ = 3.1 × 10^{− 9} cm²/s) with a marked reduction after 30 min of TNF treatment (D̄ = 0.9 × 10^{− 9} cm²/s). This reduction cannot be explained by the formation of higher ordered receptor clusters, since the fluorescence intensity of TNF treated receptors indicate the presence of a few receptor molecules per complex only. Together, these data point to a topological segregation of the two TNF receptors in different microcompartments of the plasma membrane independent of the cytoplasmic signaling domains of the receptors.

Publication metadata

Author(s): Gerken M, Krippner-Heidenreich A, Steinert S, Willi S, Neugarth F, Zappe A, Wrachtrup J, Tietz C, Scheurich P

Publication type: Article

Publication status: Published

Journal: Biochimica et Biophysica Acta: Biomembranes

Year: 2010

Volume: 1798

Issue: 6

Pages: 1081-1089

Print publication date: 23/02/2010

ISSN (print): 0005-2736

Publisher: Elsevier BV

URL: http://dx.doi.org/10.1016/j.bbamem.2010.02.021

DOI: 10.1016/j.bbamem.2010.02.021

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