Project description:At the cellular level, α-tubulin acetylation alters the structure of microtubules to render them mechanically resistant to compressive forces. How this biochemical property of microtubule acetylation relates to mechanosensation remains unknown, though prior studies have shown that microtubule acetylation influences touch perception. Here, we identify the major Drosophila α-tubulin acetylase (dTAT) and show that it plays key roles in several forms of mechanosensation. dTAT is highly expressed in the larval peripheral nervous system (PNS), but is largely dispensable for neuronal morphogenesis. Mutation of the acetylase gene or the K40 acetylation site in α-tubulin impairs mechanical sensitivity in sensory neurons and behavioral responses to gentle touch, harsh touch, gravity, and vibration stimuli, but not noxious thermal stimulus. Finally, we show that dTAT is required for mechanically-induced activation of NOMPC, a microtubule-associated transient receptor potential channel, and functions to maintain integrity of the microtubule cytoskeleton in response to mechanical stimulation.
Project description:PARP7 (TiPARP), a mono (ADP-ribosyl) transferase (MART) was found to target α-tubulin proteins in ovarian cancer cells, enhancing their growth and migration. RBN-2397 is a potent inhibitor that selectively acts on PARP7. Here, we show that RBN-2397 treatment leads to the stabilization of microtubules in ovarian cancer cells, namely α-tubulin, mimicking what was previously observed with PARP7 knockdown. When treated with RBN-2397, we observe a decrease in growth and migration of ovarian cancer cells and, interestingly, the effect is intensified upon adding the microtubule stabilizing chemotherapeutic agent, paclitaxel. Mutating the site of α-tubulin MARylation by PARP7 similarly results in α-tubulin stabilization and decreased cell migration in the presence of paclitaxel when the tubulin network is further stabilized. In sum, we demonstrate that PARP7 inhibition decreases α-tubulin MARylation resulting in its stabilization, and ultimately leading to decreased ovarian cancer cell proliferation and migration. Finally, we show that combining PARP7 inhibitor and paclitaxel results in a more robust inhibition of aggressive ovarian cancer phenotypes. Collectively, this study highlights the potential of targeting PARP7 in combination with established chemotherapeutic agents to enhance treatment efficacy for ovarian cancer.
Project description:Microtubule (MT)-based transport is an evolutionary conserved processed finely tuned by posttranslational modifications. Among them, tubulin acetylation, which is catalyzed by the α-tubulin N-acetyltransferase 1, Atat1, facilitates the recruitment and processivity of molecular motors along MT tracks. However, the mechanisms that controls Atat1 activity remains poorly understood. Here we show that a pool of vesicular ATP-citrate lyase Acly acts as a rate limiting enzyme to modulate Atat1 activity by controlling availability of Acetyl-CoA. In addition, we showed that Acly expression is reduced upon loss of Elongator activity, further connecting Elongator to Atat1 in the pathway regulating -tubulin acetylation and MT-dependent transport in projection neurons across species. Remarkably, comparable defects occur in fibroblasts from Familial Dysautonomia (FD) patients bearing an autosomal recessive mutation in the gene coding for the Elongator subunit ELP1. Our data may thus shine new light on the pathophysiological mechanisms underlying FD.