MYO18B interacts with the proteasomal subunit Sug1 and is degraded by the ubiquitin-proteasome pathway.
MYO18B is a class XVIIIB unconventional myosin encoded by a candidate tumor suppressor gene. To gain insights into the cellular function of this protein, we searched for MYO18B-interacting proteins by a yeast two-hybrid screen. Sug1, a 19S regulator subunit of the 26S proteasome, was identified as a binding partner of the C-terminal tail region of MYO18B. The association of MYO18B with Sug1 was further confirmed by GST pull-down, co-immunoprecipitation, and immunocytochemistry. Furthermore, proteasome dysfunction by a proteasome inhibitor or siRNA-mediated knock-down of Sug1 caused the up-regulation of MYO18B protein and MYO18B was polyubiquitinated in vivo. Collectively, these results suggested that MYO18B is a substrate for proteasomal degradation.
Inoue
Takeshi
T
Department of Life Sciences, Graduate School of Arts and Sciences, University of Tokyo, 3-8-1 Komaba, Tokyo 153-8902, Japan.
Kon
Takahide
T
Ajima
Rieko
R
Ohkura
Reiko
R
Tani
Masachika
M
Yokota
Jun
J
Sutoh
Kazuo
K
D000074183:ATPases Associated with Diverse Cellular Activities; D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism*; D000818:Animals; D019556:COS Cells; D002478:Cells, Cultured; D002522:Chlorocebus aethiops; D003593:Cytoplasm; D006367:HeLa Cells; D006801:Humans; D060588:LIM Domain Proteins; D009218:Myosins / Q000378:metabolism*; D046988:Proteasome Endopeptidase Complex / Q000737:chemistry* / Q000378:metabolism*; D011485:Protein Binding; D011499:Protein Processing, Post-Translational; D021381:Protein Transport; D014157:Transcription Factors / Q000378:metabolism*; D025521:Tumor Suppressor Proteins / Q000378:metabolism*; D014452:Ubiquitins / Q000378:metabolism*
D048868:Adaptor Proteins, Signal Transducing; D060588:LIM Domain Proteins; C500982:MYO18B protein, human; C092282:PSMC5 protein, human; D014157:Transcription Factors; D025521:Tumor Suppressor Proteins; D014452:Ubiquitins; D046988:Proteasome Endopeptidase Complex; D000074183:ATPases Associated with Diverse Cellular Activities; D009218:Myosins