Endocrine Abstracts

The lipid species that comprise cell membranes are not uniformly distributed. Instead different lipids can become organised into patches, or microdomains, in the membrane. These microdomains, often termed lipid rafts, can include or exclude proteins with the result that they present a locally different character compared to the surrounding membrane. Lipid rafts are enriched in cholesterol and glycosphingolipid; the saturated acyl chains of the sphingolipids promotes their dens...

For the last two decades this laboratory has been investigating the states of vitamin D and gonadal steroid hormone resistance in New World primate (platyrrhine) species. Hormone resistance results from the constitutive over-expression of proteins in the heterogeneous nuclear ribonucleoprotein (hnRNP) A and C families. These proteins, originally considered to bind and 'stabilize' single strand pre-mRNAs destined for translation, also bind DNA, regulating both the transcription...

Nuclear pore complexes (NPCs) facilitate the transport of macromolecular cargoes across the nuclear envelope by carrier molecules. The energy for this active transport mechanism is provided by the Ras-family GTPase, Ran, that orchestrates most nuclear trafficking cycles. The RanGEF (RCC1) is located in the nucleus while its GAP is located in the cytoplasm. The nuclear import of steroids, bound to their receptor, is mediated by importins alpha and beta. In the cytoplasm, import...

The hormonal form of vitamin D, calcitriol, regulates diverse cellular functions through activation of the vitamin D receptor (VDR), in a manner similar to how other ligands of nuclear receptors elicit regulation of gene transcription. Insufficient or excess calcitriol responses manifest primarily as bone diseases (rickets, osteoporosis, Paget's diseases) and hyperproliferative diseases (psoriasis and cancer). Our long-term objective is to elucidate the molecular mechanisms th...