|Title||The glaucoma-associated olfactomedin domain of myocilin is a novel calcium binding protein.|
|Publication Type||Journal Article|
|Year of Publication||2012|
|Authors||Donegan, RK, Hill, SE, Turnage, KC, Orwig, SD, Lieberman, RL|
|Journal||J Biol Chem|
|Date Published||2012 Dec 21|
|Keywords||Animals, Calcium-Binding Proteins, Cattle, Cytoskeletal Proteins, Extracellular Matrix Proteins, Eye Proteins, Glaucoma, Glycoproteins, Humans, Hydrogen-Ion Concentration, Intraocular Pressure, Mice, Mutation, Protein Structure, Tertiary, Swine, Trabecular Meshwork|
Myocilin is a protein found in the trabecular meshwork extracellular matrix tissue of the eye that plays a role in regulating intraocular pressure. Both wild-type and certain myocilin variants containing mutations in the olfactomedin (OLF) domain are linked to the optic neuropathy glaucoma. Because calcium ions are important biological cofactors that play numerous roles in extracellular matrix proteins, we examined the calcium binding properties of the myocilin OLF domain (myoc-OLF). Our study reveals an unprecedented high affinity calcium binding site within myoc-OLF. The calcium ion remains bound to wild-type OLF at neutral and acidic pH. A glaucoma-causing OLF variant, myoc-OLF(D380A), is calcium-depleted. Key differences in secondary and tertiary structure between myoc-OLF(D380A) and wild-type myoc-OLF, as well as limited access to chelators, indicate that the calcium binding site is largely buried in the interior of the protein. Analysis of six conserved aspartate or glutamate residues and an additional 18 disease-causing variants revealed two other candidate residues that may be involved in calcium coordination. Our finding expands our knowledge of calcium binding in extracellular matrix proteins; provides new clues into domain structure, function, and pathogenesis for myocilin; and offers insights into highly conserved, biomedically relevant OLF domains.
|Alternate Journal||J. Biol. Chem.|
|PubMed Central ID||PMC3527924|
|Grant List||R01 EY021205 / EY / NEI NIH HHS / United States |
R01EY021205 / EY / NEI NIH HHS / United States
The glaucoma-associated olfactomedin domain of myocilin is a novel calcium binding protein.
Submitted by enguyen7 on December 30, 2015 - 10:35am