Dual inhibitory mechanism of the truncated form of adenylyl cyclase 8 in cell signal integration: Structural and functional approaches.

Fiche publication

Date publication

novembre 2023

Journal

Biochimica et biophysica acta. Molecular cell research

Auteurs

Membres identifiés du Cancéropôle Est :
Pr DAUCHEZ Manuel , Dr DUCA Laurent

Tous les auteurs :
Legueux-Cajgfinger Y, Velusamy M, Fathallah S, Vallin B, Duca L, Dauchez M, Vincent P, Limon I, Blaise R

Lien Pubmed

https://www.ncbi.nlm.nih.gov/pubmed/38016490

Résumé

Adenylyl Cyclase 8E (AC8E), which lacks part of M1 transmembrane domain, has been previously shown to dimerize with AC3 and down-regulate its activity, but the molecular mechanism of this inhibitory effect has remained elusive. Here, we first show that AC8E also inhibits AC2 and AC6, highlighting the functional importance of this novel regulatory mechanism in the cAMP signaling pathway across AC families. We then completed the partial structure of Bos taurus AC9 using combinations of comparative modeling and fold recognition methods, and used this as a template to build the first full 3D-models of AC8 and AC8E. These models evidenced that the lack of M1 transmembrane domain of AC8E shifts the N-terminal domain, which impacts the orientation of the helical domains, thus affecting the catalytic site. This was confirmed in living cells with cAMP imaging, where we showed that the N-terminal domain is required for reducing cAMP production. Our data also show that AC8E prevents the translocation of other ACs towards the plasma membrane, further reducing the cAMP responsiveness to extracellular signals. This newly discovered dual inhibitory mechanism provides an additional level of regulation of cAMP-dependent signals integration.