Khurts Shilagardi

Keywords transmembrane topology palmitoylation trapping mutant ZMPSTE24/FACE-1 IFITM ubiquitin-proteasome system protein quality control Introduction ZMPSTE24 is a zinc metalloprotease characterized by its seven transmembrane (TM) spans that form a large intramembrane chamber enclosing an HExxH…E active site motif (H is histidine, E is glutamate, and x is any amino acid). These residues coordinate zinc (Zn2+) and carry out catalysis (1-4).

(a) Myoblast fusion defects caused by β-spectrin expression in muscle cells. Stage 15 embryos labeled with anti-MHC. Ventral lateral muscles of three hemisegments are shown in each panel. Unfused myoblasts are indicated by arrowheads. Expression of a functional, amino-terminal-tagged full-length Myc-β-Spec in all muscle cells with twi-GAL4 exacerbated the fusion defect in the β -spec-/- mutant (left panel) and caused a minor fusion defect in wild-type (right panel) embryos.