Presynaptic SNAP-25 regulates retinal waves and retinogeniculate projection via phosphorylation

Patterned spontaneous activity periodically displays in developing retinas termed retinal waves, essential for visual circuit refinement. In neonatal rodents, retinal waves initiate in starburst amacrine cells (SACs), propagating across retinal ganglion cells (RGCs), further through visual centers. Although these waves are shown temporally synchronized with transiently high PKA activity, the downstream PKA target important for regulating the transmission from SACs remains unidentified. A t-SNARE, synaptosome-associated protein of 25 kDa (SNAP-25/SN25), serves as a PKA substrate, implying a potential role of SN25 in regulating retinal development. Here, we examined whether SN25 in SACs could regulate wave properties and retinogeniculate projection during development. In developing SACs, overexpression of wild-type SN25b, but not the PKA-phosphodeficient mutant (SN25b-T138A), decreased the frequency and spatial correlation of wave-associated calcium transients. Overexpressing SN25b, but not SN25b-T138A, in SACs dampened spontaneous, wave-associated, postsynaptic currents in RGCs and decreased the SAC release upon augmenting the cAMP-PKA signaling. These results suggest that SN25b overexpression may inhibit the strength of transmission from SACs via PKA-mediated phosphorylation at T138. Moreover, knockdown of endogenous SN25b increased the frequency of wave-associated calcium transients, supporting the role of SN25 in restraining wave periodicity. Finally, the eye-specific segregation of retinogeniculate projection was impaired by in vivo overexpression of SN25b, but not SN25b-T138A, in SACs. These results suggest that SN25 in developing SACs dampens the spatiotemporal properties of retinal waves and limits visual circuit refinement by phosphorylation at T138. Therefore, SN25 in SACs plays a profound role in regulating visual circuit refinement.

Medienart:

E-Artikel

Erscheinungsjahr:

2019

Erschienen:

2019

Enthalten in:

Zur Gesamtaufnahme - volume:116

Enthalten in:

Proceedings of the National Academy of Sciences of the United States of America - 116(2019), 8 vom: 19. Feb., Seite 3262-3267

Sprache:

Englisch

Beteiligte Personen:

Hsiao, Yu-Tien [VerfasserIn]
Shu, Wen-Chi [VerfasserIn]
Chen, Pin-Chun [VerfasserIn]
Yang, Hui-Ju [VerfasserIn]
Chen, Hsin-Yo [VerfasserIn]
Hsu, Sheng-Ping [VerfasserIn]
Huang, Yi-Ting [VerfasserIn]
Yang, Cheng-Chang [VerfasserIn]
Chen, Yen-Ju [VerfasserIn]
Yu, Ni-Yen [VerfasserIn]
Liou, Shih-Yuan [VerfasserIn]
Chiang, Ning [VerfasserIn]
Huang, Chien-Ting [VerfasserIn]
Cheng, Tzu-Lin [VerfasserIn]
Cheung, Lam-Yan [VerfasserIn]
Lin, Yu-Chun [VerfasserIn]
Lu, Juu-Chin [VerfasserIn]
Wang, Chih-Tien [VerfasserIn]

Links:

Volltext

Themen:

Journal Article
PKA-mediated phosphorylation
Research Support, Non-U.S. Gov't
Retinal waves
Retinogeniculate projection
SNAP-25
Snap25 protein, mouse
Starburst amacrine cells
Synaptosomal-Associated Protein 25

Anmerkungen:

Date Completed 01.05.2019

Date Revised 09.03.2020

published: Print-Electronic

Citation Status MEDLINE

doi:

10.1073/pnas.1812169116

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM293543917