label: PH Domain
label_lc: ph domain
description: "Pleckstrin-homology (PH) domains are protein modules of approximately 120 amino acids found in a wide variety of signaling proteins in organisms ranging from yeast to humans. Some PH domains bind with high affinity (low mM or nM Kd) to specific phosphoinositides such as phosphatidyl-inositol (PI) -4,5-bisphosphate, PI-3,4-P2 or PI-3,4,5-P3. Binding to phosphoinositides may allow PH proteins to respond to lipid messengers for example by relocation to membranes. The C-termini of some PH domains have also been reported to bind the beta/lambda subunits of heterotrimeric G proteins."