The deubiquitinating enzyme USP17 blocks N-Ras membrane trafficking and activation but leaves K-Ras unaffected.
The proto-oncogenic Ras isoforms (H, N, and K) have a C-terminal CAAX motif and undergo the same post-translational processing steps, although they traffic to the plasma membrane through different routes. Previously, we have shown that overexpression of the deubiquitinating enzyme USP17 inhibits H-Ras localization to the plasma membrane. Now we report that whereas H-Ras and N-Ras were unable to localize to the plasma membrane in the presence of USP17, K-Ras4b localization was unaffected. EGF stimulation was unable to induce N-Ras membrane localization in USP17-expressing cells. In addition, N-Ras activity and downstream signaling through the MAPK MEK/ERK and PI3K/JNK pathways were blunted. However, we still detected abundant N-Ras localization at the ER and Golgi in USP17-expressing cells. Collectively, our data showed that the deubiquitinating enzyme USP17 blocks EGF-induced N-Ras membrane trafficking and activation, but left K-Ras unaffected.
Centre for Infection and Immunity, School of Medicine, Dentistry and Biomedical Sciences, Queen's University, Belfast BT9 7BL, Northern Ireland.
Michelle
M
de la Vega
James F
JF
Burrows
Cheryl
C
McFarlane
Ureshnie
U
Govender
Christopher J
CJ
Scott
James A
JA
Johnston
D001693:Biological Transport, Active / Q000187:drug effects; D020126:Brefeldin A / Q000494:pharmacology; D002462:Cell Membrane / Q000378:metabolism; D010450:Endopeptidases / Q000235:genetics / Q000378:metabolism*; D004721:Endoplasmic Reticulum / Q000378:metabolism; D004789:Enzyme Activation; D004815:Epidermal Growth Factor / Q000494:pharmacology; D006056:Golgi Apparatus / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D020935:MAP Kinase Signaling System; D011499:Protein Processing, Post-Translational; D016283:Proto-Oncogene Proteins p21(ras) / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D014162:Transfection; D064570:Ubiquitin-Specific Proteases
C117307:KRAS protein, human; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins; D020126:Brefeldin A; D004815:Epidermal Growth Factor; D010450:Endopeptidases; D064570:Ubiquitin-Specific Proteases; D016283:Proto-Oncogene Proteins p21(ras)