6nax
Olfactomedin domain of mouse myocilinOlfactomedin domain of mouse myocilin
Structural highlights
FunctionMYOC_MOUSE Secreted glycoprotein regulating the activation of different signaling pathways in adjacent cells to control different processes including cell adhesion, cell-matrix adhesion, cytoskeleton organization and cell migration. Promotes substrate adhesion, spreading and formation of focal contacts. Negatively regulates cell-matrix adhesion and stress fiber assembly through Rho protein signal transduction. Modulates the organization of actin cytoskeleton by stimulating the formation of stress fibers through interactions with components of Wnt signaling pathways. Promotes cell migration through activation of PTK2 and the downstream phosphatidylinositol 3-kinase signaling (By similarity). Plays a role in bone formation and promotes osteoblast differentiation in a dose-dependent manner through mitogen-activated protein kinase signaling (PubMed:23629661). Mediates myelination in the peripheral nervous system through ERBB2/ERBB3 signaling (PubMed:23897819). Plays a role as a regulator of muscle hypertrophy through the components of dystrophin-associated protein complex (PubMed:22371502). Involved in positive regulation of mitochondrial depolarization. Plays a role in neurite outgrowth. May participate in the obstruction of fluid outflow in the trabecular meshwork (By similarity).[UniProtKB:Q99972][1] [2] [3] Publication Abstract from PubMedMutations in myocilin, predominantly within its olfactomedin (OLF) domain, are causative for the heritable form of open angle glaucoma in humans. Surprisingly, mice expressing Tyr423His mutant myocilin, corresponding to a severe glaucoma-causing mutation (Tyr437His) in human subjects, exhibit a weak, if any, glaucoma phenotype. To address possible protein-level discrepancies between mouse and human OLFs, which might lead to this outcome, biophysical properties of mouse OLF were characterized for comparison with those of human OLF. The 1.55 A resolution crystal structure of mouse OLF reveals an asymmetric 5-bladed beta-propeller that is nearly indistinguishable from previous structures of human OLF. Wild-type and selected mutant mouse OLFs mirror thermal stabilities of their human OLF counterparts, including characteristic stabilization in the presence of calcium. Mouse OLF forms thioflavin T-positive aggregates with a similar end-point morphology as human OLF, but amyloid aggregation kinetic rates of mouse OLF are faster than human OLF. Simulations and experiments support the interpretation that kinetics of mouse OLF are faster because of a decreased charge repulsion arising from more neutral surface electrostatics. Taken together, phenotypic differences observed in mouse and human studies of mutant myocilin could be a function of aggregation kinetics rates, which would alter the lifetime of putatively toxic protofibrillar intermediates. Differential Misfolding Properties of Glaucoma-Associated Olfactomedin Domains from Humans and Mice.,Patterson-Orazem AC, Hill SE, Wang Y, Dominic IM, Hall CK, Lieberman RL Biochemistry. 2019 Mar 12. doi: 10.1021/acs.biochem.8b01309. PMID:30802039[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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