The clustering of membrane receptors such as EGFR is critical for various biological processes, for example cell signaling and tumorigenesis. However, the mechanism involved remains poorly understood. Here, we used a super resolution imaging technique, which has shattered the longstanding resolution barrier of light diffraction, to investigate the distribution of membrane EGFR on apical or basa...

PDZ domain-containing proteins such as SAP97 and ZO-1 have been implicated in the targeting and clustering of ion channels. We have explored the interactions of these polypeptides with a cardiac voltage-gated potassium channel. Immunocytochemistry in cardiac myocytes revealed colocalization of SAP97 and Kv1.5, both at the intercalated disks and the lateral membranes. Transient transfection expe...

Adenylyl cyclase (AC) isoforms catalyze the synthesis of 3',5'-cyclic AMP from ATP. These isoforms are critically involved in the regulation of gene transcription, metabolism, and ion channel activity among others. Nitric oxide (NO) is a gaseous product whose synthesis from L-arginine is catalyzed by the enzyme NO synthase. It has been well established that NO activates the enzyme guanylyl cycl...

ER and ER serve classically as transcription factors, and ER also mediates nongenomic responses to E2 such as the activation of endothelial nitric oxide synthase (eNOS). In contrast, the nongenomic capacities of endogenous ER are poorly understood. We evaluated eNOS activation by E2 in cultured endothelial cells that express endogenous ER to determine whether the ER isoform has nongenomic actio...

The human LH receptor (LHR) plays a key role in luteal function and the establishment of pregnancy through its interaction with the gonadotropins LH and human chorionic gonadotropin. We previously identified four splice variants of the LHR in human luteinized granulosa cells (LGCs) and corpora lutea (CL). Real-time quantitative PCR revealed that expression of the full-length LHR (LHRa) and the ...

Characterizing the collective functions of cytoskeletal motors is critical to understanding mechanisms that regulate the internal organization of eukaryotic cells as well as the roles various transport defects play in human diseases. Though in vitro assays using synthetic motor complexes have generated important insights, dissecting collective motor functions within living cells still remains c...

Protein kinase C (PKC)-mediated desensitization of the corticotropin releasing factor type 1 (CRF1) receptor was investigated in human retinoblastoma Y79 and transfected COS-7 cells. Because stimulation of Y79 cells with CRF resulted in large ( approximately 30-fold) increases in intracellular cAMP accumulation without changing inositol phosphate levels, the CRF1 receptor expressed in retinobla...

The insulin-regulated adipocyte/skeletal muscle glucose transporter (GLUT4) displays a characteristic steady-state intracellular localization under basal conditions, whereas the erythrocyte/brain transporter isoform (GLUT1) distributes mostly to the cell surface. To identify possible structural elements in these transporter proteins that determine their cellular localization, GLUT1/GLUT4 chimer...

BACKGROUND Ferredoxin-NADP(H) reductase (FNR) from Pisum sativum and Flavodoxin (Fld) from Anabaena PCC 7119 have been reported to protect a variety of cells and organisms from oxidative insults. In this work, these two proteins were expressed in mitochondria of Cos-7 cells and tested for their efficacy to protect these cells from oxidative stress in vitro. PRINCIPAL FINDINGS Cos-7/pFNR and C...