a b s t r a c tNerve growth factor (NGF) binding to its receptor TrkA, which belongs to the family of receptor tyrosine kinases (RTKs), is known to induce its internalization, endosomal trafficking and subsequent lysosomal degradation. The Cbl family of ubiquitin ligases plays a major role in mediating ubiquitination and degradation of RTKs. However, it is not known whether Cbl participates in mediating ubiquitination of TrkA. Here we report that c-Cbl mediates ligand-induced ubiquitination and degradation of TrkA. TrkA ubiquitination and degradation required direct interactions between c-Cbl and phosphorylated TrkA. c-Cbl and ubiquitinated TrkA are found in a complex after NGF stimulation and are degraded in lysosomes. Taken together, our data demonstrate that c-Cbl can induce downregulation of NGF-TrkA complexes through ubiquitination and degradation of TrkA.
Structured summary of protein interactions:TrkA physically interacts with c-Cbl by anti bait coimmunoprecipitation (View interaction) c-Cbl physically interacts with TrkA by anti bait coimmunoprecipitation (View interaction)
We describe a case of severe Salmonella O9 HG sepsis with a mass in the liver, which was diagnosed as hepatocellular carcinoma (HCC) by autopsy of the liver. The patient was a 67-year-old man with chronic high blood pressure. In addition, he was an alcoholic and had been drinking every day for many years. He had had a dinner of ‘sukiyaki’ with a raw egg two days before admission. The next morning, he had developed vomiting, diarrhea, and abdominal pain. Salmonella O9 HG was found in the blood and stool cultures. In the computed tomography (CT) finding of the liver, there was a 2 cm early-enhanced mass with a multilocular structure, with ringed enhancement and daughter nodes. Since we thought that the mass was a liver abscess, we performed needle aspiration from the liver mass and were able to withdraw blood. Despite adequate antibiotic treatment, the patient died as a result of complications on the 55th day after admission. After the patient’s death, we conducted an autopsy. There were two HCC masses, a moderately-differentiated and a well-differentiated mass, as a result of alcoholic cirrhosis of the liver. As the HCC had multilocular cyst-like structures, which were fiber- and necrosis-rich, CT images of the liver masses resembled abscesses.
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