2. Academic Validation
  3. Eyeless razor clam Sinonovacula constricta discriminates light spectra through opsins to guide Ca2+ and cAMP signaling pathways

Eyeless razor clam Sinonovacula constricta discriminates light spectra through opsins to guide Ca2+ and cAMP signaling pathways

  • J Biol Chem. 2023 Dec 1:105527. doi: 10.1016/j.jbc.2023.105527.
Fei Kong 1,  Zhaoshou Ran 2,  Mengqi Zhang 1,  Kai Liao 1,  Deshui Chen 3,  Xiaojun Yan 4,  Jilin Xu 5
Affiliations

Affiliations

  • 1 Key Laboratory of Aquacultural Biotechnology Ministry of Education, Ningbo University, Ningbo, Zhejiang 315211, China.
  • 2 Key Laboratory of Aquacultural Biotechnology Ministry of Education, Ningbo University, Ningbo, Zhejiang 315211, China; Key Laboratory of Marine Biotechnology of Zhejiang Province, Ningbo, Zhejiang 315211, China. Electronic address: ranzhaoshou@nbu.edu.cn.
  • 3 Fujian Dalai Seedling Technology Co., LTD, Luoyuan, Fujian 350600, China.
  • 4 Key Laboratory of Marine Biotechnology of Zhejiang Province, Ningbo, Zhejiang 315211, China.
  • 5 Key Laboratory of Aquacultural Biotechnology Ministry of Education, Ningbo University, Ningbo, Zhejiang 315211, China; Key Laboratory of Marine Biotechnology of Zhejiang Province, Ningbo, Zhejiang 315211, China; Fujian Dalai Seedling Technology Co., LTD, Luoyuan, Fujian 350600, China. Electronic address: xujilin@nbu.edu.cn.
PMID: 38043801 DOI: 10.1016/j.jbc.2023.105527
Abstract

Phototransduction is based on opsins that drive distinct types of Gα cascades. Although nonvisual photosensitivity has long been known in marine bivalves, the underlying molecular basis and phototransduction mechanism are poorly understood. Here, we introduced the eyeless razor clam Sinonovacula constricta as a model to clarify this issue. First, we showed that S. constricta was highly diverse in opsin family members, with a significant expansion in xenopsins. Second, the expression of putative S. constricta opsins was highly temporal-spatio specific, indicating their potential roles in S. constricta development and its peripheral photosensitivity. Third, by cloning four S. constricta opsins with relatively higher expression (Sc_opsin1, 5, 7, and 12), we found that they exhibited different expression levels in response to different LIGHT environments. Moreover, we demonstrated that these opsins (excluding Sc_opsin7) couple with Gαq and Gαi cascades to mediate the light-dependent CA2+ (Sc_opsin1 and 5) and cAMP (Sc_opsin12) signaling pathways. The results indicated that Sc_opsin1 and 5 belonged to Gq-opsins, Sc_opsin12 belonged to Gi-opsins, while Sc_opsin7 might act as a photo-isomerase. Furthermore, we found that the phototransduction function of S. constricta Gq-opsins was dependent on the lysine at the seventh transmembrane domain, and greatly influenced by the external LIGHT spectra in a complementary way. Thus, a synergistic photosensitive system mediated by opsins might exist in S. constricta to rapidly respond to the transient or subtle changes of the external LIGHT environment. Collectively, our findings provide valuable insights into the evolution of opsins in marine bivalves and their potential functions in nonvisual photosensitivity.

Keywords

G protein‐coupled receptor; Marine bivalves; Marine photoecology; Nonvisual photosensitivity; Photoreceptor; Phototransduction; invertebrate; rhodopsin.

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