Xu, Tianqi et al. (2017) International Worm Meeting "Gap junction networks within the motor circuit of C. elegans facilitate undulatory wave propagation."

Xu, Tianqi, Zhen, Mei, Wu, Min, Wen, Quan, Po, Michelle, Shao, Shuai, Huo, Jing

[International Worm Meeting, 2017]

Gap junction communication between neurons is prevalent in the motor circuit of invertebrates and vertebrates, yet how electrical couplings might control and coordinate locomotion during normal animal behavior remains largely elusive. The anatomical wiring diagram of C. elegans nervous system suggests that (1) the command interneuron AVB makes en passant electrical synapses with most B-type motor neurons distributed along the worm body; (2) nearby B-type motor neurons are also electrically coupled. What are the functions of gap junction highway and byway in the worm motor circuit? By combining genetic analysis, optogenetic manipulation and computational modeling, we first showed that AVB-B electrical inputs induced a bifurcation in B motor neuron dynamics, and they work synergistically with proprioceptive couplings to enhance sequential activation of motor activities and to equalize the bending amplitude along the worm body. Second, weak electrical couplings between B motor neurons could retrogradely mediate the dynamics of head bending activities. Taken together, gap junction networks within the worm motor circuit facilitate a well-formed and flexible body undulation to propagate from head to tail during C. elegans forward locomotion.

Moorthy S et al. (1996) East Coast Worm Meeting "A NOVEL C. ELEGANS ADDUCIN: A WHOLE NEW CAN OF WORMS"

Bennett V, Chen LS, Moorthy S

[East Coast Worm Meeting, 1996]

Vertebrate adducin is an actin-binding protein which can promote assembly of a spectrin-actin complex and can also act as a barbed-end actin capping protein. Biochemical and biophysical characterization in our lab has shown that active adducin is probably a tetramer consisting of two alpha subunits tightly complexed with either beta or gamma subunits. Adducin binds calmodulin and is an in vivo substrate for protein kinases C and A, all of which modulate adducin's spectrin-actin binding activity in different ways in in vitro assays. Nevertheless, vertebrate adducin has never been definitively linked to any known mutant phenotype. However mutations in a Drosophila adducin homologue, hu-li tai shao (hts), result in a female sterile phenotype in which egg chambers have fewer nurse cells, with abnormal actin distribution in the ring canals. Here we report preliminary results of our attempt to develop C. elegans as a genetic model system for adducin. We made a database search for C. elegans adducin and originally identified two partial cDNAs from Yuji Kohara's EST sequences. The first clone, yk26f2, which we call add-1 (C. elegans Adducin 1), maps to cosmid F39C12 on the left arm of LGX, close to lon-2. The 659 residue predicted protein shows significant homology to vertebrate adducin and hts in the head, neck and tail regions which suggests it may behave like the "canonical" adducins. Interestingly though, yk120b7(add-2) which lies on Cosmid F57F5 on the right arm of LGV, shows a novel structure. The C-terminal 261 residues show homology to the adducin "head" which normally lies at the N-terminus of other adducins. Instead Cad-2 has a novel 350 residue N-terminus that shows no homology in a BLAST search to known proteins. Cad-2 may use its adducin "head" to interact with Cad-1 in a heteromeric manner similar to that demonstrated for vertebrate adducins. But it also raises the exciting prospect that the adducin "head" domain may actually be a component of multiple proteins with different functions, in a manner analogous to that demonstrated for the kinesin and myosin head domains. We aim to resolve these possibilities using C. elegans as a model system.