Mutations in MYO9B are associated with Charcot-Marie-Tooth disease type 2 neuropathies and isolated optic atrophy.

Background And Purpose: Charcot-Marie-Tooth disease (CMT) is a heterogeneous group of disorders caused by mutations in at least 100 genes. However, approximately 60% of cases with axonal neuropathies (CMT2) still remain without a genetic diagnosis. We aimed at identifying novel disease genes responsible for CMT2.

The RhoGAP-myosin Myo9b regulates ocular lens pit morphogenesis.

Background: During eye development the lens placode invaginates to form the lens pit. Further bending of lens epithelium and separation from ectoderm leads eventually to a spherical lens vesicle with enclosed extracellular fluid. Changes in epithelial morphology involve the actin cytoskeleton and its regulators.

Local Myo9b RhoGAP activity regulates cell motility.

To migrate, cells assume a polarized morphology, extending forward with a leading edge with their trailing edge retracting back toward the cell body. Both cell extension and retraction critically depend on the organization and dynamics of the actin cytoskeleton, and the small, monomeric GTPases Rac and Rho are important regulators of actin. Activation of Rac induces actin polymerization and cell extension, whereas activation of Rho enhances acto-myosin II contractility and cell retraction.

Class IX Myosins: Motorized RhoGAP Signaling Molecules.

Class IX myosins are simultaneously motor and signaling molecules. In addition to myosin class-specific functions of the tail region, they feature unique motor properties. Within their motor region they contain a long insertion with a calmodulin- and a F-actin-binding site.

ER intrabody-mediated inhibition of interferon α secretion by mouse macrophages and dendritic cells.

Interferon α (IFNα) counteracts viral infections by activating various IFNα-stimulated genes (ISGs). These genes encode proteins that block viral transport into the host cell and inhibit viral replication, gene transcription and translation. Due to the existence of 14 different, highly homologous isoforms of mouse IFNα, an IFNα knockout mouse has not yet been established by genetic knockout strategies.