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C2 domain found in C2 calcium-dependent domain containing 3 (C2cd3) proteins C2cd3 is a novel C2 domain-containing protein specific to vertebrates. C2cd3 functions in regulator of cilia formation, Hedgehog signaling, and mouse embryonic development. Mutations in C2cd3 mice resulted in lethality in some cases and exencephaly, a twisted body axis, and pericardial edema in others. The presence of calcium-dependent lipid-binding domains in C2cd3 suggests a potential role in vesicular transport. C2cd3 is also an interesting candidate for ciliopathy because of its orthology to certain cilia-related genetic disease loci on chromosome. The C2 domain was first identified in PKC. 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. |
Jiyao W et al.(2023). "The conserved domain database in 2023.",