HYPK controls stability and catalytic activity of the N-terminal acetyltransferase A in Arabidopsis thaliana
Résumé
The ribosome-tethered N-terminal acetyltransferase A (NatA) acetylates 52% of soluble proteins in Arabidopsis
thaliana. This co-translational modification of the N terminus stabilizes diverse cytosolic plant proteins.
The evolutionary conserved Huntingtin yeast partner K (HYPK) facilitates NatA activity in planta, but
in vitro, its N-terminal helix a1 inhibits human NatA activity. To dissect the regulatory function of HYPK protein
domains in vivo,we genetically engineer CRISPR-Cas9 mutants expressing a HYPK fragment lacking all functional
domains (hypk-cr1) or an internally deleted HYPK variant truncating helix a1 but retaining the C-terminal
ubiquitin-associated (UBA) domain (hypk-cr2). We find that the UBA domain of HYPK is vital for stabilizing
the NatA complex in an organ-specific manner. The N terminus of HYPK, including helix a1, is critical for promoting
NatA activity on substrates starting with various amino acids. Consequently, deleting only 42 amino
acids inside the HYPK N terminus causes substantial destabilization of the plant proteome and higher tolerance
toward drought stress.
Domaines
Sciences du Vivant [q-bio]| Origine | Publication financée par une institution |
|---|---|
| Licence |
