
광수용체에서 Esyt의 Ca2+ 결합 활성이 막 접촉 부위 밀도 조절에 필요하다.


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Membrane Contact Sites (MCS) between the plasma membrane (PM) and endoplasmic reticulum (ER) have been shown to regulate Ca2+ influx into animal cells. However, the mechanisms by which cells modulate ER-PM MCS density is not understood and the role of Ca2+, if any, in regulating this process is not known. We report that in Drosophila photoreceptors, MCS density is dependent on the activity of the Ca2+ permeable channels-TRP and TRPL. This regulation of MCS density by Ca2+ is mediated by extended synaptotagmin (dEsyt), a protein localised to ER-PM MCS in photoreceptors and previously shown to regulate MCS density. We find that the Ca2+ binding activity of dEsyt is required for its functional activity in vivo . dEsytCaBM, a Ca2+ non-binding mutant of dEsyt is unable to modulate MCS structure in a manner equivalent to its wild type counterpart. Further, when reconstituted in dEsyt null photoreceptors, in contrast to wild type dEsyt, dEsytCaBM is unable to rescue ER-PM MCS density and other key phenotypes. Finally, when expressed in wild type photoreceptors, dEsytCaBM phenocopies loss of dEsyt function. Taken together, our data supports a role for the Ca2+ binding activity of dEsyt in regulating the ER-PM MCS density in photoreceptors thus tuning signal transduction in response to Ca2+ influx triggered by ambient illumination.

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### Competing Interest Statement

The authors have declared no competing interest.

 [1]: pending:yes

Ca2+ binding to Esyt is required to modulate membrane contact site density in Drosophila photoreceptors

광수용체에서-esyt의-ca2-결합이-막-접촉-부위-밀도-조절에-필요하다


광수용체에서 Esyt의 Ca2+ 결합이 막 접촉 부위 밀도 조절에 필요하다
