Nematode Extracellular Protein Interactome Expands Connections between Signaling Pathways.

Multicellularity was accompanied by the emergence of new classes of cell surface and secreted proteins. The nematode is a favorable model to study cell surface interactomes, given its well-defined and stereotyped cell types and intercellular contacts. Here we report our extracellular interactome dataset, the largest yet for an invertebrate.

Interaction between the mitochondrial adaptor MIRO and the motor adaptor TRAK.

MIRO (mitochondrial Rho GTPase) consists of two GTPase domains flanking two Ca-binding EF-hand domains. A C-terminal transmembrane helix anchors MIRO to the outer mitochondrial membrane, where it functions as a general adaptor for the recruitment of cytoskeletal proteins that control mitochondrial dynamics. One protein recruited by MIRO is TRAK (trafficking kinesin-binding protein), which in turn recruits the microtubule-based motors kinesin-1 and dynein-dynactin.

Myo19 tethers mitochondria to endoplasmic reticulum-associated actin to promote mitochondrial fission.

Mitochondrial homeostasis requires a dynamic balance of fission and fusion. The actin cytoskeleton promotes fission, and we found that the mitochondrially localized myosin, myosin 19 (Myo19), is integral to this process. Myo19 knockdown induced mitochondrial elongation, whereas Myo19 overexpression induced fragmentation.