Yaakov Egozi

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Membrane anchorage of Ras oncoproteins, required for transforming activity, depends on their carboxy-terminal farnesylcysteine. We previously showed that S-trans,trans-farnesylthiosalicylic acid (FTS), a synthetic farnesylcysteine mimetic, inhibits growth of ErbB2- and Ras-transformed cells, but not of v-Raf-transformed cells, suggesting that FTS interferes(More)
S-trans,trans-Farnesylthiosalicylic acid (FTS) is a novel farnesylated rigid carboxylic acid derivative. In cell-free systems, it acts as a potent competitive inhibitor (Ki = 2.6 microM) of the enzyme prenylated protein methyltransferase (PPMTase), which methylates the carboxyl-terminal S-prenylcysteine in a large number of prenylated proteins including(More)
Constitutively active Ras proteins, their regulatory components, and overexpressed tyrosine kinase receptors that activate Ras, are frequently associated with cell transformation in human tumors. This suggests that functional Ras antagonists may have anti-tumor activity. Studies in rodent fibroblasts have shown that S-trans, transfarnesylthiosalicylic acid(More)
The objective of the present study was to determine the binding properties of muscarinic receptors in six brain regions in mature and old rats of both sexes by employing direct binding of [3H]-antagonist as well as of the labeled natural neurotransmitter, [3H]-acetylcholine [( 3H]-AcCh). In addition, age-related factors were evaluated in the modulation(More)
Dopamine release evoked by electrical field stimulation of slices from various regions of rat brain was assessed in the presence of 10-10-10-5 M melatonin. Inhibition of dopamine release by melatonin was observed in the ventral hippocampus, medulla pons, preoptic area and median and posterior hypothalamus. No inhibitory effect of melatonin on dopamine(More)
Inhibition of Ras-dependent signaling and of oncogenic Ras function by farnesyl transferase inhibitors that block Ras membrane anchorage is limited due to alternative prenylation of Ras. Here we demonstrate that inhibition of the Ras-dependent Raf-1-MAPK (mitogen activated protein kinase) cascade is achieved by S-farnesylthiosalicylic acid (FTS) which(More)
The ligand binding properties of muscarinic receptors present in whole hypothalamus as well as in its three regions (preoptic area, median and posterior regions) were studied in male rats and mice, as well as in female rats during various stages of the estrous cycle, using the tritiated antagonist N-methyl-4-piperidyl benzilate. Kinetic and equilibrium(More)
The effect of methanol and acetone extracts of the epigeal parts of Peganum harmala, a common medicinal plant among Bedouins in Israel, was studied on several parameters of reproduction in female rats. The methanol extract at a dose of 2.5 g/kg/day, offered in food or in drinking suspension for 30 days, significantly prolonged diestrus by 1.0 day. The(More)
Inhibitors of the enzyme that methylates ras proteins, the prenylated protein methyltransferase (PPMTase), are described. They are farnesyl derivatives of rigid carboxylic acids that recognize the farnesylcysteine recognition domain of the enzyme but do not serve as substrates. They also inhibit ras-dependent cell growth by a mechanism that is probably(More)