In cell borders from immortalized Mef cells not expressing __SP__ __NODE__ protein or __SP__ __NODE__ protein , a protein chimera composed of a protein fragment ( 1508 1649 ) containing a repeat domain 11 from __SP__ __NODE__ protein and of a protein fragment ( 2282 2491 ) containing a cytoplasmic domain and a transmembrane domain from __SP__ __NODE__ protein in cell borders from immortalized Mef cells not expressing __SP__ __NODE__ protein or __SP__ __NODE__ protein increases endocytosis of __NODE__ protein .