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#intracellular signaling

3 public questions tagged with this topic.

Plasma Membrane

Which of the following lipids is involved in intracellular signaling pathways?

Phosphatidylinositol is quantitatively minor, about 5-8% of total phospholipid, but disproportionately important for intracellular signaling because its inositol ring can be phosphorylated at positions 3, 4, and 5 by dedicated kinases to generate combinatorial phosphoinositide codes. PI 4,5-bisphosphate resides in plasma membrane inner leaflet where phospholipase C, activated by Gq-coupled receptors or receptor tyrosine kinases, hydrolyzes it into two second messengers: diacylglycerol that remains membrane bound to recruit and activate conventional protein kinase C via C1 domain, and inositol

Ref: Lodish et al., Molecular Cell Biology, 9th ed., Chapter 16: Signaling, Phosphoinositide Second Messengers.

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Glycolipid and Phospholipid

Which lipid is most directly involved in intracellular signaling?

Signal transduction from surface receptors cytosol heavily relies phosphatidylinositol derivatives rather than bulk phosphatidylcholine ganglioside cholesterol structural lipids which play scaffolding roles. Plasma membrane PI phosphorylated PI4K to PI four phosphate then PIP5K to PI four five bisphosphate comprising one percent phospholipid yet pivotal recruitment PH domain proteins Dok. Ligand binding Gq coupled receptors activates PLC beta hydrolyzing PI45P2 releasing IP3 diffuses ER binding IP3R calcium channels raising cytosolic calcium one hundred nanomolar to micromolar activating calmo

Ref: Balla T., J Lipid Res 2013, Phosphoinositide signaling PI PIP2 IP3 DAG PIP3 pathway and functions.

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Cell Signaling GPCR Pathways - I

Ryanodine receptors amplify Ca2+ signaling via

positive feedback, is consistent with established principles of cell signaling, receptor pharmacology and cellular regulation. Experimental measurements of binding parameters, genetic loss-of-function studies and pharmacological interventions all converge on the same interpretation. Related options address neighboring concepts but do not satisfy the precise criterion stated in the question.

Ref: NCERT Biology Class 11–12 Alberts et al Molecular Biology of the Cell Lodish et al, Molecular Cell Biology Cooper & Hausman, The Cell Abbas et al., Cellular and Molecular Immunology (for immunology sections)

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