The Rho guanine nucleotide exchange factor AKAP13 (BRX) is essential for cardiac development in mice.

A fundamental biologic principle is that diverse biologic signals are channeled through shared signaling cascades to regulate development. Large scaffold proteins that bind multiple proteins are capable of coordinating shared signaling pathways to provide specificity to activation of key developmental genes. Although much is known about transcription factors and target genes that regulate cardiomyocyte differentiation, less is known about scaffold proteins that couple signals at the cell surface to differentiation factors in developing heart cells.

Compensatory alterations in energy homeostasis characterized in uterine tumors from hereditary leiomyomatosis and renal cell cancer.

Objective: To determine the molecular alterations that maintain energy homeostasis in hereditary leiomyomatosis and renal cell cancer (HLRCC) uterine tumors with disrupted fumarate hydratase, compared with nonsyndromic uterine tumors.

Design: Laboratory study.

Setting: Tertiary academic university hospital.

Rho family Guanine nucleotide exchange factor Brx couples extracellular signals to the glucocorticoid signaling system.

Glucocorticoids regulate many crucial biologic functions through their cytoplasmic/nuclear glucocorticoid receptors (GR). Excess, deficiency, or alteration in tissue sensitivity to glucocorticoids has been associated with major causes of human morbidity and mortality. Brx, a cytoplasmic Rho family guanine nucleotide exchange factor, binds to and influences the activity of several nuclear hormone receptors.

Expression of the proto-oncoprotein breast cancer nuclear receptor auxiliary factor (Brx) is altered in eutopic endometrium of women with endometriosis.

Objective: To evaluate the expression of estrogen receptor alpha (ERalpha), estrogen receptor beta (ERbeta), and breast cancer nuclear receptor auxiliary factor (Brx) in eutopic endometrium of normal women and women with endometriosis.

Design: Prospective observational study.

Setting: Tertiary care and research center.