EXAMINING HOW SAME-GENDER AND MIXED-GENDER COUPLES NAVIGATE SEXUAL ISSUES IN THEIR RELATIONSHIPS

Sexual scripts—the definitions and expectations that individuals hold for sexual interactions—are thought to play an important role in the maintenance of sexual well-being. Sexual scripts can be rigid or flexible, and they can be concordant or discordant between members of a couple. Sex therapists support sexual script flexibility for maintaining sexual and relationship satisfaction when couples are navigating sexual issues. However, empirical research examining the role of sexual script flexibility and the degree of script concordance/discordance in couples’ sexual well-being has been limited, due in part to the limited measures available. Furthermore, within the existing research, there has been an unfortunate tendency to exclude individuals in same-gender relationships – perpetuating the long-standing knowledge gap in the literature on positive sexuality in diverse relationships. To address these gaps in the literature, we conducted a series of online studies that recruited individuals in diverse relationships. A measure of individual sexual script flexibility in response to sexual issues was developed (Chapter 2); in addition, the structure of an existing measure assessing couple sexual scripts in response to a sexual issue was evaluated (Chapter 3). Chapter 4 examined how individuals in diverse relationships compared on measures of individual sexual script flexibility and on couple sexual scripts. Findings suggest that there are more similarities than differences across diverse couples. Chapter 5 explored how flexibility in an individual’s approach to sexual issues relates to sexual well-being, specifically by assessing sexual communication and partner responses as mediators. Results suggest that individual sexual script flexibility relates to sexual well-being through reciprocal partner processes. Collectively, this research program suggests that more similarities than differences exist between individuals in same- and mixed-gender relationships, and that partners are important to consider in the relationship between individual sexual script flexibility and sexual well-being. These findings have implications for sex and couple therapy; these results emphasize the importance of interventions that target both members of the couple, and further our understanding of sexuality in same- and mixed-gender relationships.

Structural and functional studies of bacterial protein tyrosine kinases

While protein tyrosine kinases (PTKs) have been extensively characterized in eukaryotes, far less is known about their emerging counterparts in prokaryotes. Studies of close to 20 homologs of bacterial protein tyrosine (BY) kinases have inaugurated a blooming new field of research, all since just the end of the last decade. These kinases are key regulators in the polymerization and exportation of the virulence-determining polysaccharides which shield the bacterial from the non-specific defenses of the host. This research is aimed at furthering our understanding of the BY kinases through the use of X-ray crystallography and various in vitro and in vivo experiments. We reported the first crystal structure of a bacterial PTK, the C-terminal kinase domain of E. coli tyrosine kinase (Etk) at 2.5Å resolution. The fold of the Etk kinase domain differs markedly from that of eukaryotic PTKs. Based on the observed structure and supporting evidences, we proposed a unique activation mechanism for BY kinases in Gram-negative bacteria. The phosphorylation of tyrosine residue Y574 at the active site and the specific interaction of P-Y574 with a previously unidentified key arginine residue, R614, unblock the Etk active site and activate the kinase. Both in vitro kinase activity and in vivo antibiotics resistance studies utilizing structure-guided mutants further support the novel activation mechanism. In addition, the level of phosphorylation of their C-terminal Tyr cluster is known to regulate the translocation of extracellular polysaccharides. Our studies have significantly clarified our understanding of how the phosphorylation status on the C-terminal tyrosine cluster of BY kinases affects the oligomerization state of the protein, which is likely the machinery of polysaccharide export regulation. In summary, this research makes a substantial contribution to the rapidly progressing research of bacterial tyrosine kinases.