Villagra, A. | Search bioRxiv

bioRxiv2026

HDAC6 and SSAT2 orchestrate acetyllysine metabolism and protein homeostasis

Lysine acetylation is a prevalent and dynamic posttranslational modification, yet the metabolic fate and physiological role of free N {varepsilon}-acetyl-L-lysine (AcK) remain unclear. Here, we identify opposing enzyme-catalyzed reactions linking lysine/AcK homeostasis to protein stability. We show that the first catalytic domain of HDAC6 stereospecifically deacetylates free AcK, establishing HDAC6 as an N {varepsilon}-acyl-lysine deacylase. AcK functions both as a recyclable lysine reservoir and as a signaling metabolite that elevates -tubulin acetylation and suppresses cell migration. Conversely, SSAT2 acetylates free lysine in cells and undergoes substrate-dependent C-terminal autoacetylation. We demonstrate that C-terminal lysine acetylation constitutes a reversible proteasomal degradation signal that promotes SSAT2 degradation and may extend to additional proteins bearing a terminal lysine. Stabilization of SSAT2 by HDAC6-dependent deacetylation, together with intricate regulation affected by substrate availability, reveals a novel mechanism that couples amino acid recycling to cytoskeletal dynamics and proteostasis.

biochemistry↗

bioRxiv2019

Is the replication crisis a problem for biologists? A geometric morphometric approach.

Replicability of findings is the key factor of scientific reliability. However, literature on this topic is scarce and apparently taboo for large scientific areas. Some authors named the failure to reproduce scientific findings replication crisis. Geometric morphometrics, a vastly used technique, is especially silent on replication crisis concern. Nevertheless, some works pointed out that sharing morphogeometric information is not a trivial fact, but need to be careful and meticulous. Here, we investigated the replicability of geometric morphometrics protocols on complex shapes and measurement error extension in three different types of taxa, as well as the potentiality of these protocols to discriminate among closely related species. We found a wide range of replication error that contributed from 19.5% to 60% of the total variation. Although, measurement error decreased with the complexity of the quantified shape, it often maintained high values. All protocols were able to discriminate between species, but more morphogeometric information does not imply better performance. We present evidence of replication crisis in life sciences and highlight the need to explore in deep different sources of variation that could lead to low replicability findings. Lastly, we enunciate some recommendations in order to improve the replicability and reliability of scientific findings.

scientific communication and education↗