Analyse der LIMP-2 (Lysosomales Integrales Membranprotein 2) defizienten Maus
LIMP-2 is a glycosylated lysosomal membrane protein which spans the membrane twice. It is mainly localised in lysosomes and late endosomes, small amounts are also found in early endosomes and at the plasma membrane. LIMP-2 deficiency in mice leads to a phenotype with a triade of features: (i) a peripheral neuropathy, caused by reduced expression of the myelin proteins; (ii) deafness, beginning with the loss of potassium channels KCNQ1/KCNE1 in the stria vascularis, followed by an atrophy of this tissue and the loss of the hair cells; and (iii) an ureter stenosis, which is associated with reduced levels of uroplakins in the uroepithelium and is followed by the development of hydronephrosis. The three types of cellular abnormalities have in common that the affected cells are polarised epithelia and the disturbed expression is only affecting proteins that are localised at the apical membrane. We assume that LIMP-2 might play an important role in the endocytic recycling compartment (ERC), which is believed to be the sorting station for apicaly localised proteins.