The cell wall is a real drag.

M artinière et al. (1), at long last, take a critical look at the general mobility of proteins in the plant plasma membrane. Hundreds of studies looking at the active or diffusion-limited transport of proteins in the animal cell plasma membrane paint a complex picture. There are mammalian proteins that wander the membrane aimlessly, proteins corralled into pens by the cytoskeleton, proteins that become stuck in a cholesterolrich mud, and even proteins that anchor themselves to the ECM (2). From these broader findings, it appears clear that animal cells exploit the restriction of proteins to a 2D lipid plane for complex outcomes. At issue in plant cells is almost every property that has ever been ascribed to the transport of a plasma membrane protein in a cellular system. A systematic study of how different classes of membrane proteins move within the plant plasma membrane simply has not been done.