Cell wall constrains lateral diffusion of plant plasma-membrane proteins

Abstract

A cell membrane can be considered a liquid-phase plane in which lipids and proteins theoretically are free to diffuse. Numerous reports, however, describe retarded diffusion of membrane proteins in animal cells. This anomalous diffusion results from a combination of structuring factors including protein-protein interactions, cytoskeleton corralling, and lipid organization into microdomains. In plant cells, plasma-membrane (PM) proteins have been described as relatively immobile, but the control mechanisms that structure the PM have not been studied. Here, we use fluorescence recovery after photobleaching to estimate mobility of a set of minimal PM proteins. These proteins consist only of a PM-anchoring domain fused to a fluorescent protein, but their mobilities remained limited, as is the case for many full-length proteins. Neither the cytoskeleton nor membrane microdomain structure was involved in constraining the diffusion of these proteins. The cell wall, however, was shown to have a crucial role in immobilizing PM proteins. In addition, by single-molecule fluorescence imaging we confirmed that the pattern of cellulose deposition in the cell wall affects the trajectory and speed of PM protein diffusion. Regulation of PM protein dynamics by the plant cell wall can be interpreted as a mechanism for regulating protein interactions in processes such as trafficking and signal transduction.

The dynamics of plant plasma membrane proteins: PINs and beyond

“…3). In this scenario, after sorting to polar plasma membrane domains, PINs, like other membrane proteins, accumulate in membrane clusters that exhibit a low tendency to diffuse laterally, thereby contributing to the maintenance of an already established polar protein distribution Martiniere et al, 2012). Moreover, there is evidence for enhanced clathrin-dependent endocytic sorting of PIN proteins, specifically at sites proximal to PIN-enriched plasma membrane domains .…”

“…1). This involves lateral diffusion within the plasma membrane, which has been implicated as an important determinant for controlling protein-protein interactions and is suggested to influence rates of intracellular sorting of membrane proteins (Singer and Nicolson, 1972;Simons and Ikonen, 1997;Kleine-Vehn et al, 2011;Martiniere et al, 2012). Internalized plasma membrane proteins in general undergo endocytic sorting from the plasma membrane into sorting endosomes, which constitute components of the trans-Golgi network/early endosome (TGN/EE), followed by either recycling to domains at the plasma membrane or further sorting into late endosomes/multivesicular bodies (MVBs) for their ultimate degradation in the lytic vacuole (Murphy et al, 2005;Jürgens and Geldner, 2007;Schellmann and Pimpl, 2009;Zarsky and Potocky, 2010;Reyes et al, 2011;Robinson and Pimpl, 2013).…”

A Mathematical Model for the Coreceptors SOMATIC EMBRYOGENESIS RECEPTOR-LIKE KINASE1 and SOMATIC EMBRYOGENESIS RECEPTOR-LIKE KINASE3 in BRASSINOSTEROID INSENSITIVE1-Mediated Signaling

“…This is based on the findings of Kinoshita et al (2005), reporting that the dissociation constant between BRI1 and BL of 7.4 nM (Wang et al, 2001) remains unaltered in the absence of BAK1 (SERK3). Finally, although Arabidopsis plasma membrane-localized proteins are relatively immobile (Martinière et al, 2012), spatial inhomogeneity is not explicitly modeled.…”

Mobility of Group 1b Remorins in Membrane Nanodomains Differs Significantly between Mesophyll Cells and Protoplasts

“…To our knowledge no similar datasets exists at this time concerning FRAP-experiments with sterol-dependent plasma membrane proteins in Arabidopsis. However, we note that others have had similar results of other plasma membrane proteins in plants [19]. In yeast FRAP, experiments were performed involving the sterol-dependent proteins Pma1 and Sso1, which are forming patchy-patterns in vital plasma membranes.…”

“…FRAP-experiments revealed that components of the cell wall have a stabilizing effect regarding the mobility of single Remorin proteins within individual nanodomains. Suggestions of this general concept have been made previously [19] but not for steroldependent plasma membrane proteins that compartmentalize. In intact mesophyll tissue single eGFP::StRem1.3 fusion proteins did not show a fluorescence recovery ( Figure 3A).…”