Double C2-domain protein (Doc2) is a Ca(2+)-binding protein implicated in asynchronous and spontaneous neurotransmitter release. Here we demonstrate that each of its C2 domains senses Ca(2+); moreover, the tethered tandem C2 domains display properties distinct from the isolated domains. We confirm that overexpression of a mutant form of Doc2β, in which two acidic Ca(2+) ligands in the C2A domai...

Store-operated Ca(2+) entry (SOCE) is established by formation of subplasmalemmal clusters of the endoplasmic reticulum (ER) protein, stromal interacting molecule 1 (STIM1) upon ER Ca(2+) depletion. Thereby, STIM1 couples to plasma membrane channels such as Orai1. Thus, a close proximity of ER domains to the plasma membrane is a prerequisite for SOCE activation, challenging the concept of local...

Caveolae are plasma membrane invaginations enriched in sterols and sphingolipids. Sphingosine kinase 1 (SK1) is an oncogenic protein that converts sphingosine to sphingosine 1-phosphate (S1P), which is a messenger molecule involved in calcium signaling. Caveolae contain calcium responsive proteins, but the effects of SK1 or S1P on caveolar calcium signaling have not been investigated. We genera...

The regulation of Ca in human body is performed by Ca-ATPase. The affinity of erythrocyte plasma membrane Ca-ATPase (PMCA) was examined for three different porphyrin compounds, Tetraphenylporphinesulfonate (TPPS), 5,10,15,20-Tetrakis (4-sulfonatophenyl) porphyrinato Iron(III) Chloride (FeTPPS) and 5,10,15,20-Tetrakis (4-sulfonatophenyl) porphyrinato Iron(III) nitrosyl Chloride (FeNOTPPS), by en...

OBJECTIVE To examine the effect of Ca(2+) store depletion on the translocation of vanilloid transient receptor potential (TRPV) 4-C1 heteromeric channels to the plasma membrane. METHODS AND RESULTS Vesicular trafficking is a key mechanism for controlling the surface expression of TRP channels in the plasma membrane, where they perform their function. TRP channels in vivo are often composed of...

The relationships between the effects of procaine and those of Ca on the spontaneous electrical and mechanical activities of smooth muscle cells of the guinea pig urinary bladder were studied using both microelectrode and sucrose gap methods. Procaine(1, 7, and 15mM) depolarized the membrane and increased spontaneous spike freqency. The maximum rates of rise and fall and the after-hyperpolariza...

The epithelial Ca(2+) channel TRPV5 constitutes the apical entry gate for Ca(2+) transport in renal epithelial cells. Ablation of the trpv5 gene in mice leads to a reduced Ca(2+) reabsorption. TRPV5 is tightly regulated by various calciotropic hormones, associated proteins, and other factors, which mainly affect channel activity via the C terminus. To further identify the role of the C terminus...

BACKGROUND Macrolides show high minimum inhibitory concentrations (MICs) against Pseudomonas aeruginosa when tested in recommended media (cation-adjusted Muller-Hinton broth [CA-MHB]). Nevertheless, azithromycin is successfully used in cystic fibrosis patients, supposedly because of "nonantibiotic effects." METHODS CA-MHB and Roswell Park Memorial Institute (RPMI) 1640 medium (used for growin...

Background and Purpose—Experimental evidence supports a major role of increased intracellular calcium [Ca]i levels in the induction of neuronal damage during cerebral ischemia. However, the source of Ca rise has not been fully elucidated. To clarify further the role and the origin of Ca in cerebral ischemia, we have studied the effects of various pharmacological agents in an in vitro model of o...

Plant cell growth and stress signaling require Ca²⁺ influx through plasma membrane transport proteins that are regulated by reactive oxygen species. In root cell growth, adaptation to salinity stress, and stomatal closure, such proteins operate downstream of the plasma membrane NADPH oxidases that produce extracellular superoxide anion, a reactive oxygen species that is readily converted to ext...