The geometry of cellular membranes is a highly conserved phenotype, however the molecular mechanisms by which it impacts cellular function are not fully understood. We hypothesized that the strictly regulated membrane geometry has an important role in the distribution and regulation of membrane proteins and thereby cellular function. This thesis is based on three manuscripts that utilize fluorescence microscopy to investigate how membrane curvature in living cells can actively modulate protein sorting and function. First, we explored how changes in the mean membrane curvature of tubular filopodia structures influence membrane curvature sensing and generation by I-BAR domains. Second, we developed a live cell assay that can acquire topography maps of the plasma membrane of living cell with an axial resolution of 3.1 ± 1 nm. This allowed us to investigate sorting of plasma membrane associated proteins in correlation with arbitrary membrane geometries. Finally, we explore how distinct membrane geometries affect the sorting and function of two prototypical family A GPCRs, where we suggest that membrane curvature can act as a regulator for receptor activation probability. The results of this thesis thereby suggest that membrane curvature can act as a modulator of membrane protein sorting and function and should not be a neglected factor when studying the function of membrane protein.