An intrinsic compartmentalization code for peripheral membrane proteins in photoreceptor neurons.

In neurons, peripheral membrane proteins are enriched in subcellular compartments, where they play key roles, including transducing and transmitting information. However, little is known about the mechanisms underlying their compartmentalization. To explore the roles of hydrophobic and electrostatic interactions, we engineered probes consisting of lipidation motifs attached to fluorescent proteins by variously charged linkers and expressed them in rod photoreceptors.

Steric volume exclusion sets soluble protein concentrations in photoreceptor sensory cilia.

Proteins segregate into discrete subcellular compartments via a variety of mechanisms, including motor protein transport, local binding, and diffusion barriers. This physical separation of cell functions serves, in part, as a mechanism for controlling compartment activity by allowing regulation of local protein concentrations. In this study we explored how soluble protein size impacts access to the confined space within the retinal photoreceptor outer segment signaling compartment and discovered a strikingly steep relationship.