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C2 domain present in Phosphoinositide-specific phospholipases C (PLC) PLCs are involved in the hydrolysis of phosphatidylinositol-4,5-bisphosphate (PIP2) to d-myo-inositol-1,4,5-trisphosphate (1,4,5-IP3) and sn-1,2-diacylglycerol (DAG). 1,4,5-IP3 and DAG are second messengers in eukaryotic signal transduction cascades. PLC is composed of a N-terminal PH domain followed by a series of EF hands, a catalytic TIM barrel and a C-terminal C2 domain. C2 domains fold into an 8-standed beta-sandwich that can adopt 2 structural arrangements: Type I and Type II, distinguished by a circular permutation involving their N- and C-terminal beta strands. Many C2 domains are Ca2+-dependent membrane-targeting modules that bind a wide variety of substances including bind phospholipids, inositol polyphosphates, and intracellular proteins. Most C2 domain proteins are either signal transduction enzymes that contain a single C2 domain, such as protein kinase C, or membrane trafficking proteins which contain at least two C2 domains, such as synaptotagmin 1. However, there are a few exceptions to this including RIM isoforms and some splice variants of piccolo/aczonin and intersectin which only have a single C2 domain. C2 domains with a calcium binding region have negatively charged residues, primarily aspartates, that serve as ligands for calcium ions. Members here have a type-II topology. |
Jiyao W et al.(2023). "The conserved domain database in 2023.",