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Rab38 trafficking and membrane targeting mediated by a potential c‐terminus palmitoylation mechanism
Author(s) -
Zhang Linghui,
Lee MengTse,
Lambright David,
Huang Shaohui
Publication year - 2011
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.25.1_supplement.955.4
Subject(s) - palmitoylation , prenylation , microbiology and biotechnology , chemistry , endosome , golgi apparatus , gtpase , small gtpase , rab , cysteine , biochemistry , biology , intracellular , cell , signal transduction , enzyme
Rab38, a small GTPase regulating surfactant trafficking in lung alveolar type II cells, contains a c‐terminus CaaX motif suggesting a farnesylation and palmitoylation mechanism similar to those of Ras proteins. Mutations to the cysteine residue (C208) and the upstream one (C205) separately or in combination abolish WT EGFP‐Rab38 labeling of the late endosome (LE) and lysosome (LY) membranes in MLE‐15 cells. Consistent with the palmitoylation hypothesis, EGFP‐Rab38 is found to extensively colocalize with ERGIC (Rab1) and Golgi (giantin) markers. However, EGFP‐Rab38 is not present in the Rab8A‐positive exocytic vesicles originated from TGN, suggesting palmitoylation targets Rab38 to LE/LB but not to the plasma membrane of the lung epithelium cell line. We have been working on a metabolic labeling protocol using “click” chemistry and fluorescence detection to elucidate the details of the farnesylation/palmitoylation mechanism. Supported by NIH 5T32HL007748 and P01HL19737.