Biomedical subjects

L G Rodriguez

Publications and source records attributed to L G Rodriguez.

3 recordsLinked to original sources

PubMed2001

Identification of a novel interaction between integrin beta1 and 14-3-3beta.

Integrins are cell surface receptors for extracellular matrix, which play important roles in a variety of biological processes. 14-3-3 proteins are a highly conserved family of cytoplasmic proteins that associate with several intracellular signaling molecules in regulation of various cellular functions. Here, we report identification of an interaction between the integrin beta1 cytoplasmic domain and 14-3-3beta by using the yeast two-hybrid screen. Like several other proteins, the integrin beta1 cytoplasmic domain associated with 14-3-3beta by a non-phosphoserine mechanism. The 14-3-3beta/integrin beta1 interaction was confirmed by in vitro binding assays as well as co-precipitation in vivo. Furthermore, we found that 14-3-3beta co-localized with integrin beta1 during the early stage of cell spreading on fibronectin, suggesting a potential role of the 14-3-3beta/integrin beta1 interaction in the regulation of cell adhesion. Using tetracycline-regulated expression system, we showed that overexpression of 14-3-3beta stimulated cell spreading and migration on fibronectin but not on poly-L-lysine. However, the induced expression of 14-3-3beta did not affect tyrosine phosphorylation of FAK or its substrates, p130(cas) and paxillin, suggesting that 14-3-3beta regulated integrin-mediated cell spreading and migration by FAK-independent mechanisms. Taken together, these results identify an interaction between integrin and 14-3-3 proteins and suggest a potentially novel cellular function for 14-3-3 proteins in the regulation of integrin-mediated cell adhesion and signaling events.

14-3-3 Proteins↗

PubMed1997

Charge interactions in sperm-egg recognition.

A novel method using derivatized agarose beads for investigating the types of molecules, when isolated from all others, that can form stable adhesive bonds, was recently described by Roque et al. (1996). The findings from this study were extended to living sea urchin cell systems. Both the bead results and the experiments with sea urchin cells suggested that phosphorylated amino acids can form stable adhesive bonds with positively charged peptides (Roque et al., 1996). As these experiments only examined phosphorylated amino acids, the validity of the hypotheses developed in the earlier study was dependent on extending the experiments to additional phosphorylated molecules. In this study, effects of D-mannose, D-mannose-1-phosphate, D-fructose, D-fructose-1-phosphate, maltose and maltose-1-phosphate on embryo cell reaggregation and sperm-egg interaction using untreated, jelly coat-free and vitelline layer disrupted Strongylocentrotus purpuratus sea urchin eggs were examined. The phosphorylated sugars (50 mM), and not their non-phosphorylated counterparts, strongly inhibited fertilization of the 3 types of eggs. ATP, at concentrations as low as 0.8 mM also completely inhibited fertilization. The phosphorylated sugars had little or no effect on reaggregating sea urchin blastula cells. A likely explanation of these results is that sperm-egg interaction in the sea urchin involves positively and negatively charged receptors; the positively charged receptors are blocked by exogenously added phosphorylated molecules. These and earlier studies indicate that by extending results from bead modeling studies to living systems, interesting information can be obtained regarding bonding mechanisms that may modulate adhesive interactions.

Adenosine Triphosphate↗

PubMed1986

Effect of life in industrialized societies on hearing in natives of Easter Island.

In an effort to determine whether life in industrialized societies can have an effect on hearing, 90 natives from Easter Island over 45 years old were evaluated. They underwent complete clinical and audiological assessment and were divided into groups according to those having lived only on the island or those having lived in modern civilization. With all factors being equal, except exposure to modern civilization, our results showed that living in civilized societies has a significant negative effect on hearing; the severity is directly proportional to the years of exposure. The median hearing thresholds of natives always living on the island (men and women combined) was found to be similar to those of female citizens of the United States; there was no significant difference in hearing thresholds between men and women among these natives. These results suggest that there are no significant inherent racial differences nor significant inherent differences between males and females in the sensitivity of hearing. A relationship between aging and hearing was noted and interpreted as true or intrinsic presbycusis. There were no cases of otosclerosis, Meniere's disease, or exostoses of the external ear canal among natives who had always lived on the island. Pure natives were found not to be prone to otitis media in spite of having an extremely high incidence of severe upper respiratory tract allergies.

Aged↗