Independent membrane protein clustering

Fancy models aren't necessary to explain how membrane proteins huddle together in clusters. Findings from Jochen Sieber, Thorsten Lang (Max Planck Institute, Göttingen, Germany), and colleagues reveal that clusters are one membrane protein's natural state.

Most membrane proteins form small, organized multicopy domains. Scientists have hoped that lipid rafts might explain this compartmentalization. But Lang isn't convinced. “There are too many types of domains to explain by lipids alone,” he says. “Lipid–lipid interactions would not mediate enough specificity.”

A newer model suggests that cytoskeletal proteins form fences and pickets that corral proteins. “But then how do you get diversity?” asks Lang. “Proteins are just sorted by size. It can only explain a limited number of areas.”

Neither model explains why two very similar membrane fusion proteins, syntaxins 1 and 4, segregate into different clusters....