Phosphoinositides are critical regulators of ion channel and transporter activity. Defects in interactions inwardly rectifying potassium (Kir) channels with phosphoinositides lead to disease. ATP-sensitive K(+) (K(ATP)) unique among Kir that they serve as metabolic sensors, inhibited by ATP while stimulated long-chain (LC) acyl-CoA. Here we show K(ATP) the least specific their activation demonstrate LC acyl-CoA these depends on low phosphoinositide specificity. We provide a systematic...

Activation of several inwardly rectifying K⁺ channels (Kir) requires the presence phosphatidylinositol 4,5-bisphosphate (PtdIns(4,5)P₂). The constitutively active Kir2.1 (IRK1) interact with PtdIns(4,5)P₂ strongly, whereas G-protein activated Kir3.1/3.4 (GIRK1/GIRK4), show only weak interactions PtdIns(4,5)P₂. We investigated whether these displayed distinct specificities for different phosphoinositides. IRK1, but not GIRK1/GIRK4 channels, showed a...

Inwardly rectifying potassium (Kir) channels play an important role in setting the resting membrane potential and modulating excitability. We have recently shown that cholesterol regulates representative members of Kir family majority cases, suppresses channel function. Furthermore, recent data indicate by specific sterol-protein interactions, yet location binding site is unknown. Using a combined computational-experimental approach, we show may bind to two nonanular hydrophobic regions...

A variety of ion channels are regulated by cholesterol, a major lipid component the plasma membrane whose excess is associated with multiple pathological conditions. However, mechanism underlying cholesterol sensitivity unknown. We have recently shown that an increase in suppresses inwardly rectifying K(+) (Kir2) responsible for maintaining potential cell types. Here we show Kir2 depends on specific region C terminus cytosolic domain channel, CD loop. Within this loop, L222I mutation Kir2.1...

Highlights•Epilepsy-related Slack channel mutants increase maximal open probability•Seven related to epilepsy enhance sodium sensitivity of channel•The Y775H mutant directly facilitates binding channel•Two exhibit their over-activity only in high intracellular concentrationSummaryTwelve sodium-activated potassium (KCNT1, Slack) genetic have been identified from severe early-onset patients. The changes biophysical properties these and the underlying mechanisms causing disease remain elusive....

Transient receptor potential canonical type 5 (TRPC5) ion channels are expressed in the brain and kidney have been identified as promising therapeutic targets whose selective inhibition can protect against diseases driven by a leaky filter, such focal segmental glomerular sclerosis. TRPC5 activated not only elevated levels of extracellular Ca2+or lanthanide ions but also G protein (Gq/11) stimulation. Phosphatidylinositol 4,5-bisphosphate (PIP2) hydrolysis phospholipase C enzymes leads to...

Activation of heterotrimeric GTP-binding (G) proteins by their coupled receptors, causes dissociation the G protein α and βγ subunits. Gβγ subunits interact directly with protein-gated inwardly rectifying K+ (GIRK) channels to stimulate activity. In addition, free subunits, resulting from agonist-independent can account for a major component basal channel activity.Using series chimeric constructs between GIRK4 Gβγ-insensitive channel, IRK1, we have identified critical site interaction GIRK...

P2X receptors are ATP-gated nonselective cation channels highly permeable to calcium that contribute nociception and inflammatory responses. The 4 subtype, upregulated in activated microglia, is thought play a critical role the development of tactile allodynia following peripheral nerve injury. Posttranslational regulation function crucial cellular mechanisms neuropathic pain, however it remains poorly understood. Here, we show phosphoinositides PI(4,5)P 2 (PIP ) PI(3,4,5)P 3 ), products...

Slo2 Na(+)-activated potassium channels are widely expressed in neurons and other cells, such as kidney, heart, skeletal muscle. Although their important physiological roles continue to be appreciated, molecular determinants responsible for sensing intracellular Na(+) remain unknown. Here we report identification of an regulatory site, similar coordination motif described Kir channels, localized the RCK2 domain Slo2.2 channels. Molecular simulations homology-modeled provided structural...

Molybdenum disulfide (MoS2) nanomaterial has recently found various applications in the biomedical field mainly due to its outstanding physicochemical properties. However, little is known about interactions with biological systems at atomic level, which intimately relates biocompatibility of material. To provide insights into effects MoS2 entities, we investigated proteins from a functionally important membrane family, ubiquitous potassium (K+) channels. Here, study four representative K+...

TMEM16A channels pass Ca 2+ -activated Cl - currents that drive a plethora of fundamental physiological processes. are activated by rise in intracellular levels but also require interactions with the signaling phospholipid phosphatidylinositol 4,5-bisphosphate (PIP 2 ) to gate open. Although PIP is essential for activity many types ion channels, its precise binding site and role channel gating remain poorly understood most cases, limiting efforts study dynamics design targeted modulators. In...

G protein-sensitive inwardly rectifying potassium (GIRK) channels are activated through direct interactions of their cytoplasmic N- and C-terminal domains with the βγ subunits proteins. By using a combination biochemical electrophysiological approaches, we identified minimal Gβγ-binding responsible for stimulation GIRK4 channel activity. Within these one N-terminal residue, His-64, Leu-268, proved critical Gβγ-mediated Moreover, mutations at sites reduced significantly binding to Gβγ. The...