Lupo et al. MUTATIONS IN THE SH3TC2 PROTEIN CAUSING CHARCOT-MARIE-TOOTH DISEASE TYPE 4C AFFECT ITS LOCALIZATION IN THE PLASMA MEMBRANE AND ENDOCYTIC PATHWAY Vincenzo Lupo1,2, Máximo I. Galindo1,2, Dolores Martínez-Rubio1,2, Teresa Sevilla3,4, Juan J. Vílchez3,4, Francesc Palau1,2, Carmen Espinós2. 1. Genetics and Molecular Medicine Unit, Instituto de Biomedicina de Valencia (IBV), CSIC, 46010 Valencia, Spain. 2. CIBER de Enfermedades Raras (CIBERER), 46010 Valencia, Spain. 3. Neurology Service, Hospital Universitari La Fe, 46009 Valencia, Spain. 4. CIBER de Enfermedades Neurodegenerativas (CIBERNED), 46009 Valencia, Spain. Corresponding author: Dr, Francesc Palau Genetics and Molecular Medicine Unit Instituto de Biomedicina de Valencia (IBV), CSIC c/ Jaume Roig, 11. 46010 Valencia, Spain Fax: + 34 96 369 0800 Telephone number: + 34 96 339 3773 Email:
[email protected] 1 Lupo et al. Abstract (250 words) Mutations in SH3TC2 cause Charcot-Marie-Tooth disease (CMT) type 4C, a demyelinating inherited neuropathy characterized by early onset and scoliosis. Here we demonstrate that SH3TC2 is expressed in several components of the endocytic pathway including early endosomes, late endosomes and clathrin-coated vesicles close to the trans-Golgi network, and in the plasma membrane. Myristoylation of SH3TC2 in glycine 2 is necessary but not sufficient for the proper location of the protein in the cell membranes. In addition to myristoylation, correct anchoring also needs the presence of SH3 and TPR domains. Mutations that cause a stop codon and produce premature truncations that remove most of the TPR domains are expressed as the wild type protein. In contrast, missense mutations in or around the region of the first TPR domain are not expressed in early endosomes, have reduced expression in plasma membrane and late endosomes, and are variably expressed in clathrin-coated vesicles.