For polytopes P1, P2 ⊂ R we consider the intersection P1 ∩ P2, the convex hull of the union CH(P1 ∪ P2), and the Minkowski sum P1 + P2. For Minkowski sum we prove that enumerating the facets of P1+P2 is NPhard if P1 and P2 are specified by facets, or if P1 is specified by vertices and P2 is a polyhedral cone specified by facets. For intersection we prove that computing the facets or the vertice...

Phosphorylated phosphoinositide lipids (PPIs) are low-abundance signaling molecules that control signal transduction pathways and are necessary for cellular homeostasis. The PPI phosphatidylinositol (3,5)-bisphosphate (PI(3,5)P2) is essential in multiple organ systems. PI(3,5)P2 is generated from PI3P by the conserved lipid kinase Fab1/PIKfyve. Defects in the dynamic regulation of PI(3,5)P2 are...

The concept of pollution prevention, or "P2," signifies a new, proactive environmental mindset that targets the causes, rather than the consequences, of polluting activity. While anecdotal evidence suggests that P2 opportunities exist and that many have been pursued, there is also the perception that the pace of P2 is far too slow. To explore that claim--and to shed light on barriers to P2 inno...

Phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2) is a versatile phospholipid that participates in many membrane-associated signaling processes. PI(4,5)P2 production at the plasma membrane (PM) depends on levels of its precursor, phosphatidylinositol 4-phosphate (PI4P), synthesized principally by two intracellular enzymes, PI4-kinases IIIα and IIIb; the former is preferentially inhibited by phe...

Transient receptor potential classical (or canonical) (TRPC)3, TRPC6, and TRPC7 are a subfamily of TRPC channels activated by diacylglycerol (DAG) produced through the hydrolysis of phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2) by phospholipase C (PLC). PI(4,5)P2 depletion by a heterologously expressed phosphatase inhibits TRPC3, TRPC6, and TRPC7 activity independently of DAG; however, the ...

LPS binds sequentially to CD14 and TLR4/MD2 receptor triggering production of proinflammatory mediators. The LPS-induced signaling is controlled by a plasma membrane lipid PI(4,5)P2 and its derivatives. Here, we show that stimulation of murine peritoneal macrophages with LPS induces biphasic accumulation of PI(4,5)P2 with peaks at 10 and 60-90 min that were still seen after silencing of TLR4 ex...

Silswal N, Parelkar NK, Wacker MJ, Brotto M, Andresen J. Phosphatidylinositol 3,5-bisphosphate increases intracellular free Ca in arterial smooth muscle cells and elicits vasocontraction. Am J Physiol Heart Circ Physiol 300: H2016–H2026, 2011. First published March 18, 2011; doi:10.1152/ajpheart.01011.2010.—Phosphoinositide (3,5)-bisphosphate [PI(3,5)P2] is a newly identified phosphoinositide t...

Sperm protamine deficiency has been associated with human male infertility. However, the aetiology of deregulated protamine expression remains elusive. The objective of this study was to evaluate the underlying aetiology of protamine deficiency in male infertility patients with deregulated protamine expression. Protamine-1 (P1) and protamine-2 (P2) protein concentrations were compared against P...

The lateral stalk of ribosome is responsible for kingdom-specific binding of translation factors and activation of GTP hydrolysis that drives protein synthesis. In eukaryotes, the stalk is composed of acidic ribosomal proteins P0, P1 and P2 that constitute a pentameric P-complex in 1: 2: 2 ratio. We have determined the solution structure of the N-terminal dimerization domain of human P2 (NTD-P2...