A knockout of the Tsg101 gene leads to decreased expression of ErbB receptor tyrosine kinases and induction of autophagy prior to cell death.

The Tumor Susceptibility Gene 101 (Tsg101) encodes a multi-domain protein that mediates a variety of molecular and biological processes including the trafficking and lysosomal degradation of cell surface receptors. Conventional and conditional knockout models have demonstrated an essential requirement of this gene for cell cycle progression and cell viability, but the consequences of a complete ablation of Tsg101 on intracellular processes have not been examined to date. In this study, we employed mouse embryonic fibroblasts that carry two Tsg101 conditional knockout alleles to investigate the expression of ErbB receptor tyrosine kinases as well as stress-induced intracellular processes that are known to be associated with a defect in growth and cell survival.

Effect of invariant chain on major histocompatibility complex class I molecule expression and stability on human breast tumor cell lines.

Invariant chain (Ii) binds to the human leukocyte antigen (HLA) class II molecule and assists it in the process of peptide acquisition. In addition, Ii binds to the HLA class I molecule, although there has been little study of its effects on the HLA class I molecule. In addition to its normal expression on antigen-presenting cells, Ii expression is up regulated in a variety of tumors.

Association of intracellular proteins with folded major histocompatibility complex class I molecules.

The major histocompatibility complex (MHC) class I molecule is responsible for presenting peptide antigens at the cell surface for recognition by cytotoxic T lymphocytes. Several chaperone molecules interact with the MHC class I heavy chain and release when the MHC groove folds around peptide. Two additional proteins, invariant chain and amyloid precursor-like protein 2 (APLP2), interact specifically and stably with MHC class I molecules that have folded peptide-binding grooves.

Inhibition by allyl sulfides and phenethyl isothiocyanate of methyl-n-pentylnitrosamine depentylation by rat esophageal microsomes, human and rat CYP2E1, and Rat CYP2A3.

Garlic and Cruciferae are associated with reduced risks of several human cancers, and some of their constituents are anticarcinogenic in animals. Here we studied inhibition of in vitro metabolism of the rat esophageal carcinogen methyl-n-pentylnitrosamine (MPN) by garlic-derived allyl sulfides and by Cruciferae-derived phenethyl isothiocyanate (PEITC) and sulforaphane. The test inhibitors were incubated with [3H]-MPN, NADPH-generating system and rat esophageal microsomes (REM) or a cytochrome P450 (CYP).

N-nitroso compounds in the gastrointestinal tract of rats and in the feces of mice with induced colitis or fed hot dogs or beef.

Because colonic N-nitroso compounds (NOC) may be a cause of colon cancer, we determined total NOC levels by Walters' method in the gastrointestinal tract and feces of rodents: (i) feces of C57BL mice fed chow and semi-purified diets contained 3.2 +/- 0.4 and 0.

The amyloid precursor-like protein 2 and the adenoviral E3/19K protein both bind to a conformational site on H-2Kd and regulate H-2Kd expression.

A protein of unknown physiological function, called amyloid precursor-like protein 2 (APLP2), forms an association with the murine class I molecule K(d) that is up-regulated by the presence of the adenoviral protein E3/19K. We have extended these findings to show that APLP2 and E3/19K associate preferentially with folded K(d) and not with the open form. APLP2 was detectable at the cell surface, but its surface expression was not up-regulated by the concurrent expression of K(d).