Anthony Vecchiarelli @cellforganized.bsky.social · 11hOur Biochem Dept is hiring! Come join us! Please Repost! 👍 0710
Anthony Vecchiarelli @cellforganized.bsky.social · 19/09/2026Applications are now being accepted for the 2027 Bacterial Cell Biology & Development GRC, June 6–11! GRS will be on June 5-6, 2027 We’ll likely be oversubscribed, so please apply early! 26738
Anthony Vecchiarelli @cellforganized.bsky.social · 19/08/2026Special thanks to Robyn Roth and Ursula Goodenough for contributing these BEAUTIFUL Deep Etch EM images of PolyP associating with Carboxysomes! 040
Anthony Vecchiarelli @cellforganized.bsky.social · 26/05/2026Happy to welcome @ayushpanda2002.bsky.social to the Vecchiarelli lab! Can't quite put my finger on it, but something told me he'd be a perfect fit. 090
Anthony Vecchiarelli @cellforganized.bsky.social · 01/05/2026#GoBlue Congratulations Dr Claudia Mak and Dr Claire Dudley! 081
Anthony Vecchiarelli @cellforganized.bsky.social · 13/04/2026Overall, we find polyP is a spatial regulator of the photosynthetic cytoplasm and establishes metabolic polymers like polyP as active, global architects of intracellular structure rather than passive storage molecules. 161
Anthony Vecchiarelli @cellforganized.bsky.social · 13/04/2026We also asked whether polyP metabolism more broadly shapes photosynthetic cell organization. In ΔppK2 cells, polyP-like “pockets” wetted to thylakoid. In ΔppX cells, polyP granules were inside carboxysomes! 140
Anthony Vecchiarelli @cellforganized.bsky.social · 13/04/2026Yes! In addition to defects in carboxysome assembly and organization, ΔppK1 cells exhibited a massive growth defect when grown in ambient CO2. 120
Anthony Vecchiarelli @cellforganized.bsky.social · 13/04/2026Deletion of the kinase, PPK1, eliminates polyP granules, and results in more numerous, smaller, and more dynamic carboxysomes, suggesting polyP plays a role in proper carboxysome assembly, organization, and maybe function? From left to right: wt, ΔppK1, ΔppK2, ΔppX. 130
Anthony Vecchiarelli @cellforganized.bsky.social · 13/04/2026Having shown that carboxysomes have no influence on polyP, we asked if the carboxysomes-polyP association changes when carboxysomes are mispositioned. Strikingly, carboxysomes cluster at PolyP granules in McdAB mutant strains! (McdAB is the carboxysome positioning system) 130
Anthony Vecchiarelli @cellforganized.bsky.social · 13/04/2026Despite their physical association with carboxysomes, polyP granules do not depend on carboxysomes for their formation or spatial organization. 140
Anthony Vecchiarelli @cellforganized.bsky.social · 12/12/2025Just got word that we are a go for the Bacterial Cell Biology and Development GRS and GRC at Southern New Hampshire University! GRS will be on June 5-6, 2027 GRC will be from June 6-11, 2027 Block off your calendars Prokaryotic Cell Biologists! More details to come! Please repost! 36337
Anthony Vecchiarelli @cellforganized.bsky.social · 23/09/2025The capacity to engineer both the composition of compartments and their positioning advances synthetic biology into a new era, where the spatial context of cellular function (“where”) can be programmed as readily as its content (“what”). This was a massive team effort. Congrats to all authors! 010
Anthony Vecchiarelli @cellforganized.bsky.social · 23/09/2025By fusing this MapTag to heterologous organelles and co-expressing McdA, we reprogramed the distribution of condensates, encapsulins, and even membrane-bound organelles in E. coli! 100
Anthony Vecchiarelli @cellforganized.bsky.social · 23/09/2025We then repurposed McdAB as a generalized spatial regulator for other bacterial organelles. An N-terminal peptide of McdB is necessary and sufficient for McdA interaction. We developed this McdB peptide into a minimal autonomous positioning tag or “MapTag”. 100
Anthony Vecchiarelli @cellforganized.bsky.social · 23/09/2025We also observed carboxysome “partitioning,” where the shell appears to invaginate at the midpoint of a larger carboxysome, suggesting that McdAB may play a role in carboxysome size regulation by subdividing oversized structures. 110
Anthony Vecchiarelli @cellforganized.bsky.social · 23/09/2025Without McdAB, CryoET shows large and disorganized aggregates of carboxysome components at the cell poles. By contrast, McdAB-expressing cells displayed fully assembled, properly sized, and unclustered carboxysomes distributed across the nucleoid region of the cell! 162
Anthony Vecchiarelli @cellforganized.bsky.social · 23/09/2025First, we showed that McdAB can distribute carboxysomes in E. coli! 100
Anthony Vecchiarelli @cellforganized.bsky.social · 23/09/2025Carboxysome organization is mediated by the Maintenance of Carboxysome Distribution (Mcd) system. McdB binds carboxysomes and induces McdA, a ParA-type ATPase, to oscillate along the nucleoid and distribute carboxysomes in the cell. 100
Anthony Vecchiarelli @cellforganized.bsky.social · 23/09/2025The most extensively studied bacterial organelle is the carboxysome, a protein-based organelle found in autotrophic bacteria that is responsible for significant global CO₂-fixation and holds promise for biotech applications. 110
Anthony Vecchiarelli @cellforganized.bsky.social · 23/09/2025We set out to determine if this conserved evolutionary strategy across diverse bacteria and cargo-types can be used a blueprint for engineering a generalizable method for programming spatial control in bacteria. 100
Anthony Vecchiarelli @cellforganized.bsky.social · 23/09/2025Bacteria encode self-organizing systems comprised of a ParA positioning ATPase and a partner protein that links these ATPases to diverse cellular cargoes. These modules distribute chromosomes, plasmids, protein complexes, and organelles across the bacterial world. 100
Anthony Vecchiarelli @cellforganized.bsky.social · 23/09/2025This asymmetric distribution results in a loss of inheritance across the cell population, compromising activity and constraining applications. 100
Anthony Vecchiarelli @cellforganized.bsky.social · 23/09/2025These compartments have drawn interest as modular building blocks for synthetic biology. Yet, a central challenge limits their use: when expressed in heterologous hosts such as E. coli, the nucleoid acts as a diffusion barrier. 110
Anthony Vecchiarelli @cellforganized.bsky.social · 23/09/2025In bacteria, protein-based microcompartments, encapsulins and condensates, as well as membrane-bound organelles, concentrate and regulate reactions without the complex endomembrane systems of eukaryotes. 120
Anthony Vecchiarelli @cellforganized.bsky.social · 14/07/2025Lab made me a calendar for my bday. Here is July. Canadian tuxedos in full effect 🇨🇦 4190
Anthony Vecchiarelli @cellforganized.bsky.social · 30/05/2025We propose that, with ParA family ATPases, positioning and partitioning are mechanistically separable: weak interactions with the partner can mediate positioning, whereas effective partitioning requires stronger interactions capable of overcoming cargo self-association forces. 000
Anthony Vecchiarelli @cellforganized.bsky.social · 30/05/2025Our findings and math modelling suggest that weakened McdA–McdB interactions are sufficient to maintain carboxysome clusters on the nucleoid but inadequate for partitioning individual carboxysomes across it. 100
Anthony Vecchiarelli @cellforganized.bsky.social · 30/05/2025We identify 3 Lys residues whose individual substitution modulates McdA binding and leads to distinct carboxysome organization phenotypes. Notably, Lys 7 substitutions result in a single carboxysome cluster at mid-nucleoid. Unlike an McdB deletion where carboxysomes cluster at the cell poles. 100
Anthony Vecchiarelli @cellforganized.bsky.social · 30/05/2025McdB belongs to a widespread but poorly characterized class of ParA partner proteins that connect it to the carboxysome cargo. The basis of its interaction with McdA remains unclear. We find that the N-terminal 20 residues of McdB are necessary and sufficient for interaction with McdA. 100
Anthony Vecchiarelli @cellforganized.bsky.social · 30/05/2025The McdAB system spatially organize carboxysomes to promote efficient carbon fixation and ensure their equal inheritance during cell division. McdA, a ParA family ATPase, forms dynamic gradients on the nucleoid that position McdB-bound carboxysomes. 100
Anthony Vecchiarelli @cellforganized.bsky.social · 07/05/2025Huge thanks to Anthony Hyman for an outstanding Connell Lecture at the University of Michigan! 🌟 His talk on phase separation was both inspiring and thought-provoking. 👏🧪 From Cacio e Pepe to Proteins, phase separation is everywhere! 😜 @hymanlab.bsky.social 030
Anthony Vecchiarelli @cellforganized.bsky.social · 25/04/2025We show that a compacted nucleoid maintains carboxysome organization in the absence of active McdAB-driven positioning. This finding reveals that the nucleoid is not merely a passive substrate for positioning, but an active player in spatial organization in bacteria. 110
Anthony Vecchiarelli @cellforganized.bsky.social · 25/04/2025So if it's not McdAB, how do carboxysomes remain distributed in metabolically dormant cells?? Nucleoid Compaction! 100
Anthony Vecchiarelli @cellforganized.bsky.social · 25/04/2025Is the McdAB system really burning up ATP to position carboxysomes in metabolically inactive cells?? Nope. McdA and McdB are down-regulated in metabolically dormant cells! 100
Anthony Vecchiarelli @cellforganized.bsky.social · 25/04/2025Here, we investigated how nucleoid compaction impacts carboxysome positioning, particularly during metabolic dormancy. Interestingly, stationary phase cells have beautifully distributed carboxysomes that align straight down the midline of the cell 100
Anthony Vecchiarelli @cellforganized.bsky.social · 25/04/2025In the cyanobacterium Synechococcus elongatus PCC 7942, a ParA-like ATPase McdA (red) binds the nucleoid and interacts with its partner protein, McdB, to generate dynamic gradients that distribute carboxysomes (cyan) across the nucleoid. 100
Anthony Vecchiarelli @cellforganized.bsky.social · 25/04/2025The nucleoid is not just a genetic repository—it's dynamic scaffold for spatially organizing key cellular cargos. ParA-family ATPases use the nucleoid to position a wide range of cargos, yet how nucleoid compaction influences positioning remains poorly understood. 110
Anthony Vecchiarelli @cellforganized.bsky.social · 02/04/2025Chatting with someone at the door Anthony 100
