dictyNews

Electronic Edition

Volume 49, number 5

February 17, 2023



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Abstracts

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Field model for multistate lateral diffusion of various

transmembrane proteins observed in living Dictyostelium cells



Kazutoshi Takebayashi, Yoichiro Kamimura and Masahiro 

Ueda





Journal of Cell Science (2023) 136, jcs260280. 

doi:10.1242/jcs.260280



The lateral diffusion of transmembrane proteins on plasma

membranes is a fundamental process for various cellular 

functions.Diffusion properties specific for individual protein species 

have been extensively studied, but the common features among 

protein species are poorly understood. Here, we systematically 

studied the lateral diffusion of various transmembrane proteins in 

the lower eukaryoteDictyostelium discoideum cells using a hidden 

Markov model for single-molecule trajectories obtained 

experimentally. As common features, all membrane proteins that 

had from one to ten transmembrane regions adopted three free 

diffusion states with similar diffusion coefficients regardless of their 

structural variability.All protein species reduced their mobility 

similarly upon the inhibition of microtubule or actin cytoskeleton 

dynamics, or myosin II. The relationship between protein size and 

the diffusion coefficient was consistent with the Saffman–Delbrück 

model, meaning that membrane viscosity is a major determinant of 

lateral diffusion, but protein size is not. These protein species-

independent properties of multistate free diffusion were explained 

simply and quantitatively by free diffusion on the three membrane 

regions with different viscosities, which is in sharp contrast to the 

complex diffusion behavior of transmembrane proteins in higher 

eukaryotes.





Submitted by Kazutoshi Takebayashi [[log in to unmask]]

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[End dictyNews, volume 49, number 5]