PT  - JOURNAL ARTICLE
AU  - Heather A. Van Epps
AU  - Mitsuko Hayashi
AU  - Louise Lucast
AU  - George W. Stearns
AU  - James B. Hurley
AU  - Pietro De Camilli
AU  - Susan E. Brockerhoff
TI  - The Zebrafish <em>nrc</em> Mutant Reveals a Role for the Polyphosphoinositide Phosphatase Synaptojanin 1 in Cone Photoreceptor Ribbon Anchoring
AID  - 10.1523/JNEUROSCI.2892-04.2004
DP  - 2004 Oct 06
TA  - The Journal of Neuroscience
PG  - 8641--8650
VI  - 24
IP  - 40
4099  - http://www.jneurosci.org/content/24/40/8641.short
4100  - http://www.jneurosci.org/content/24/40/8641.full
SO  - J. Neurosci.2004 Oct 06; 24
AB  - Visual, vestibular, and auditory neurons rely on ribbon synapses for rapid continuous release and recycling of synaptic vesicles. Molecular mechanisms responsible for the properties of ribbon synapses are mostly unknown. The zebrafish vision mutant nrc has unanchored ribbons and abnormal synaptic transmission at cone photoreceptor synapses. We used positional cloning to identify the nrc mutation as a premature stop codon in the synaptojanin1 (synj1) gene. Synaptojanin 1 (Synj1) is undetectable in nrc extracts, and biochemical activities associated with it are reduced. Furthermore, morpholinos directed against synj1 phenocopy the nrc mutation. Synj1 is a polyphosphoinositide phosphatase important at conventional synapses for clathrin-mediated endocytosis and actin cytoskeletal rearrangement. In the nrc cone photoreceptor pedicle, not only are ribbons unanchored, but synaptic vesicles are reduced in number, abnormally distributed, and interspersed within a dense cytoskeletal matrix. Our findings reveal a new role for Synj1 and link phosphoinositide metabolism to ribbon architecture and function at the cone photoreceptor synapse.