1. Divalent Cations and Redox Conditions Regulate the Molecular Structure and Function of Visinin-Like Protein-1
- Author
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Kobe, B, Wang, CK, Simon, A, Jessen, CM, Oliveira, CLP, Mack, L, Braunewell, K-H, Ames, JB, Pedersen, JS, Hofmann, A, Kobe, B, Wang, CK, Simon, A, Jessen, CM, Oliveira, CLP, Mack, L, Braunewell, K-H, Ames, JB, Pedersen, JS, and Hofmann, A
- Abstract
The NCS protein Visinin-like Protein 1 (VILIP-1) transduces calcium signals in the brain and serves as an effector of the non-retinal receptor guanylyl cyclases (GCs) GC-A and GC-B, and nicotinic acetyl choline receptors (nAchR). Analysis of the quaternary structure of VILIP-1 in solution reveals the existence of monomeric and dimeric species, the relative contents of which are affected but not exclusively regulated by divalent metal ions and Redox conditions. Using small-angle X-ray scattering, we have investigated the low resolution structure of the calcium-bound VILIP-1 dimer under reducing conditions. Scattering profiles for samples with high monomeric and dimeric contents have been obtained. The dimerization interface involves residues from EF-hand regions EF3 and EF4.Using monolayer adsorption experiments, we show that myristoylated and unmyristoylated VILIP-1 can bind lipid membranes. The presence of calcium only marginally improves binding of the protein to the monolayer, suggesting that charged residues at the protein surface may play a role in the binding process.In the presence of calcium, VILIP-1 undergoes a conformational re-arrangement, exposing previously hidden surfaces for interaction with protein partners. We hypothesise a working model where dimeric VILIP-1 interacts with the membrane where it binds membrane-bound receptors in a calcium-dependent manner.
- Published
- 2011