Biology subjects

Sindoni, N.

Publications and source records attributed to Sindoni, N..

2 recordsLinked to original sources

bioRxiv2024

Autophagosomes coordinate an AKAP11-dependent regulatory checkpoint that shapes neuronal PKA signaling

Protein Kinase A (PKA) is regulated spatially and temporally via scaffolding of its catalytic (C/{beta}) and regulatory (RI/RII) subunits by the A-kinase-anchoring proteins (AKAP). PKA engages in poorly understood interactions with autophagy, a key degradation pathway for neuronal cell homeostasis, partly via its AKAP11 scaffold. Mutations in AKAP11 drive schizophrenia and bipolar disorders (SZ-BP) through unknown mechanisms. Through proteomic-based analysis of immunopurified lysosomes, we identify the C-RI-AKAP11 holocomplex as a prominent autophagy-associated protein kinase complex. AKAP11 scaffolds C-RI to the autophagic machinery via its LC3-interacting region (LIR), enabling both PKA regulation by upstream signals, and its autophagy-dependent degradation. We identify Ser83 on the RI linker-hinge region as an AKAP11-dependent phospho-residue that modulates RI-C binding and cAMP-induced PKA activation. Decoupling AKAP11-PKA from autophagy alters Ser83 phosphorylation, supporting an autophagy-dependent checkpoint for PKA signaling. Ablating AKAP11 in induced pluripotent stem cell-derived neurons reveals dysregulation of multiple pathways for neuronal homeostasis. Thus, the autophagosome is a novel platform that modulate PKA signaling, providing a possible mechanistic link to SZ/BP pathophysiology.

cell biology↗

bioRxiv2024

De novo pyrimidine biosynthesis inhibition synergizes with BCL-XL targeting in pancreatic cancer

Oncogenic KRAS, the genetic driver of 90% of pancreatic adenocarcinoma (PDAC), induces a metabolic rewiring characterized, in part, by dependency on de novo pyrimidine biosynthesis. Pharmacologic inhibition of dihydroorotate dehydrogenase (DHODH), an enzyme in the de novo pyrimidine synthesis pathway, delays pancreatic tumor growth in vivo; however, limited monotherapy efficacy suggests compensatory pathways and that combinatorial strategies are required for enhanced efficacy. Here, we use an integrated metabolomic, quantitative temporal proteomic and in vitro and in vivo DHODH inhibitor anchored CRISPR/Cas9 genetic screening approach to identify compensatory pathways to DHODH inhibition (DHODHi) and targets for combination strategies. We demonstrate that DHODHi alters the apoptotic regulatory proteome thereby enhancing sensitivity to inhibitors of the anti-apoptotic BCL2L1 (BCL-XL) protein. Combinatorial regimens with DHODH and BCL-XL inhibition synergistically induce apoptosis in PDAC cell lines and patient-derived PDAC organoids. In vivo DHODH inhibition with Brequinar and BCL-XL degradation with DT2216, a proteolysis targeting chimera (PROTAC), significantly inhibits the growth of PDAC tumors. Our data defines mechanisms of adaptation to DHODH inhibition and identifies a combination therapy strategy in PDAC.

cancer biology↗