No abstract

A stimulatory GDP/GTP exchange protein for smg p21 is active on the post-translationally processed form of c-Ki-ras p21 and rhoA p21 (ras ABSTRACTWe have purified a stimulatory GDP/GTP exchange protein for smg p21A and -B, ras p21-like small GTP-binding proteins (G proteins), cloned its cDNA, and named it GDP dissociation stimulator (smg p21 GDS). We show here that smg p21 GDS is active not only on smg p21A and -B but also on c-Ki-ras p21 and rhoA p21, all of which are post-translationally processed. Furthermore, we show that smig p21 GDS is inactive on the post-translationally unprocessed form of these proteins and on the post-translationally processed form of c-Ha-ras p21 and smg p25A. All of the small G proteins recognized by smg p21 GDS have a cDNA-predicted C-terminal "CAAX" motif (where C is cysteine, A is an aliphatic amino acid, and X is any amino acid) and a polybasic region upstream of this motif. These results suggest that smg p21 GDS is at least active on a group of small G proteins having these unique C-terminal structures. Moreover, they suggest that the C-terminal post-translational processing of these small G proteins, by farnesylation or geranylgeranylation of the C-terminal cysteine residue, removal of amino acids in positions denoted "AAX", and carboxyl methylation of the exposed cysteine residue, is important for the sing p21 GDS action.

Objectives: To examine the validity and reproducibility of a self-administered foodfrequency questionnaire (FFQ) used for two cohort studies in Japan. Design: Cross-sectional study. Setting: Two rural towns in the Miyagi Prefecture, in north-eastern Japan. Subjects: Fifty-five men and 58 women. Results: A 40-item FFQ was administered twice, 1 year apart. In the mean time, four 3-day diet records (DRs) were collected in four seasons within the year. We calculated daily consumption of total energy and 15 nutrients, 40 food items and nine food groups from the FFQs and the DRs. We computed Spearman correlation coefficients between the FFQs and the DRs. With adjustment for age, total energy and deattenuation for measurement error with the DRs, the correlation coefficients for nutrient intakes ranged from 0.25 to 0.58 in men and from 0.30 to 0.69 in women, with median of 0.43 and 0.43, respectively. Median (range) of the correlation coefficients was 0.35 (2 0.30 to 0.72) in men and 0.34 (2 0.06 to 0.75) in women for food items and 0.60 (20.10 to 0.76) and 0.51 (0.28 -0.70) for food groups, respectively. Median (range) of the correlation coefficients for the two FFQs administered 1 year apart was 0.49 (0.31-0.71) in men and 0.50 (0.40-0.64) in women for nutrients, 0.43 (0.14 -0.76) and 0.45 (0.06-0.74) respectively for food items, and 0.50 (0.30 -0.70) and 0.57 (0.39-0.66) respectively for food groups. Relatively higher agreement percentages for intakes of nutrients and food groups with high validity were obtained together with lower complete disagreement percentages. Conclusions: The FFQ has a high reproducibility and a reasonably good validity, and is useful in assessing the usual intakes of nutrients, foods and food groups among a rural Japanese population.

No abstract

Ninlp, a component of the 26S proteasome of Saccharomyces cerevisiae, is required for activation of Cdc28p kinase at the G1-S-phase and G2-M boundaries. By exploiting the temperature-sensitive phenotype of the ninl-l mutant, we have screened for genes encoding proteins with related functions to Ninlp and have cloned and characterized two new multicopy suppressors, SUNI and SlUN2, of the ninl-l mutation. SUNI can suppress a null ninl mutation, whereas SlUN2, an essential gene, does not. Sunlp is a 268-amino acid protein which shows strong similarity to MBP1 of Arabidopsis thaliana, a homologue of the S5a subunit of the human 26S proteasome. Sunlp binds ubiquitin-lysozyme conjugates as do S5a and MBP1. Sun2p (523 amino acids) was found to be homologous to the p58 subunit of the human 26S proteasome. cDNA encoding the p58 component was cloned. Furthermore, expression of a derivative of p58 from which the N-terminal 150 amino acids had been removed restored the function of a null allele of SUN2. During glycerol density gradient centrifugation, both Sunlp and Sun2p comigrated with the known proteasome components. These results, as well as other structural and functional studies, indicate that both Sunlp and Sun2p are components of the regulatory module of the yeast 26S proteasome.