Alpha interaction domain

Several lines of evidence show that there is a specific region in the intracellular loop between domains I and II of the a, subunit that serves as the primary site for binding of P subunits. This site has been named the alpha interaction domain (AID Pragnell et al., 1994). Cavps contain a beta interaction domain (BID) that, until very recently, was thought to serve as the primary site for interaction with the a, subunit (DeWaard et al., 1994). However, resolution of the structure of Ca2+ channel P subunits has indicated that such a view may be oversimplified. 

Skiba, N. P., Yang, C. S., Huang, T., Bae, H., and Hamm, H. E. (1999). The alpha-helical domain of Gat determines specific interaction with regulator of G protein signaling 9./. Biol. Chem. 274, 8770-8778. 

A leucine zipper is a structural motif present in a large class of transcription factors. These dimeric proteins contain two extended alpha helices that grip the DNA molecule much like a pair of scissors at adjacent major grooves. The coiled-coil dimerization domain contains precisely spaced leucine residues which are required for the interaction of the two monomers. Some DNA-binding proteins with this general motif contain other hydrophobic amino acids in these positions hence, this structural motif is generally called a basic zipper. 

Sulentic, C., et. al., Interactions at a dioxin responsive element (DRE) and an overlapping kappaB site within the hs4 domain of the 3 alpha immunoglobulin heavy chain enhancer, Toxicology, 200, 235, 2004. 

Meigs, T. E., Fields, T. A., McKee, D. D., and Casey, P.J. (2001). Interaction of G alpha 12 and G alpha 13 with the cytoplasmic domain of cadherin provides a mechanism for beta-catenin release. Proc. Natl. Acad. Sci. USA 98, 519-524. 

Caulfield MP, Jones S, Vallis Y, Buckley NJ, Kim GD, Milligan G, Brown DA (1994) Muscarinic M-current inhibition via G alpha q/11 and alpha-adrenoceptor inhibition of Ca2+ current via G alpha o in rat sympathetic neurones. J Physiol 477 Pt 3 415-22 Charvin N, L Eveque C, Walker D, Berton F, Raymond C, KataokaM, Shoji-Kasai Y, Takahashi M, De Waard M, Seagar MJ (1997) Direct interaction of the calcium sensor protein synaptotagmin I with a cytoplasmic domain of the alphal A subunit of the P/Q-type calcium channel. Embo J 16 4591-6... 

Fig. 1 Structure of the neuronal SNAREs. Upper panel domain structure of the three neuronal SNARE proteins involved in synaptic vesicle fusion. Syntaxin 1A and SNAP-25 (contains two SNARE motifs) are associated with the presynaptic membrane, whereas synaptobrevin 2 is synaptic vesicle associated. The SNARE motifs form a stable complex (core complex) whose crystal structure has been analyzed (lower panel). In the complex, each of the SNARE motifs adopts an alpha-helical structure, and the four alpha-helices are aligned in parallel forming a twisted bundle (modified from Sutton et al. 1998). Stability of the complex is mediated by layers of interaction (—7 to +8) in which amino acids from each of the four alpha-helices participate (see text).

Brenman JE, Chao DS, Gee SH, McGee AW, Craven SE, Santillano DR, Wu Z, et al. (1996) Interaction of nitric oxide synthase with the postsynaptic density protein PSD-95 and alpha 1-syntrophin mediated by PDZ domains. Cell 84 757-67 Broillet MC, Firestein S (1996) Direct activation of the olfactory cyclic nucleotide-gated channel through modification of sulfhydryl groups by NO compounds. Neuron 16 377-85... 

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