Year: 2020
Type: article
Abstract: The ordered environment of membrane rafts is thought to exclude many transmembrane proteins. Nevertheless, some multi-pass transmembrane proteins have been proposed to partition into ordered domains. Here, giant plasma membrane vesicles (GPMVs) were employed to quantitatively show that the tetraspan peripheral myelin protein 22 (PMP22) exhibits a pronounced preference for, promotes the formation of, and stabilizes ordered membrane domains. Neither S-palmitoylation of PMP22 nor its putative cholesterol binding motifs are required for partitioning to ordered domains. In contrast, disruption of its unusual first transmembrane helix (TM1) reduced ordered phase preference. Charcot-Marie-Tooth disease-causing mutations that destabilize PMP22 also reduced or eliminated this preference in favor of the disordered phase. These studies demonstrate PMP22’s ordered phase preference derives both from the distinctive properties of TM1 and global structural features associated with its transmembrane domain, providing a first glimpse at the structural factors that promote raft partitioning for multi-pass proteins. Significance Statement The preferential partitioning of single span membrane proteins for the ordered phase of ordered/disordered phase-separated membranes is now reasonably well understood, but little is known about this phase preferences of multi-pass membrane proteins. Here, it is shown that the disease-linked tetraspan integral membrane protein, PMP22, displays a pronounced preference to partition into the ordered phase, a preference that is reversed by disease mutations. This phase preference may be related to the role of PMP22 in cholesterol homeostasis in myelinating Schwann cells, a role that is also known to be disrupted under conditions of CMTD peripheral neuropathy caused by pmp22 mutations.
Language: English
Subfield: Molecular Biology
Domain: Life Sciences
Open Access status: hybrid
Funders: Vanderbilt University, National Institutes of Health, National Eye Institute, National Cancer Institute, National Institute of General Medical Sciences, National Institute of Diabetes and Digestive and Kidney Diseases, National Institute of Neurological Disorders and Stroke, Vanderbilt Institute of Chemical Biology, School of Medicine, Vanderbilt University
Awards: G1149166549, G1344704808, G2019238319, G2567620825, G3025209238, Vanderbilt Mouse Metabolic Phenotyping Center, G3183709489, G3485139178, G3865556588, Vanderbilt Mouse Metabolic Phenotyping Center, G4293071939, G4320917349, G5853943267, G5877334990, G610520840, G678101785, G7220527126, G725763919, G814828431, G9000002043, G9000052974, G9000060478, G9000081609, G9000106052, G9000122305, G9000159340, Molecular and Cellular Basis for Digestive Diseases, Vanderbilt Diabetes Research Center, Core Grant in Vision Research
OpenAlex ID: W3033220126