Biology subjects

Cruz, E. R.

Publications and source records attributed to Cruz, E. R..

3 recordsLinked to original sources

bioRxiv2026

Proteome-wide quantification of protein turnover in frog and fly embryos reveals divergent strategies of maternal inheritance

Every embryo inherits a maternal proteome that it must remodel with zygotic proteins to build its many cell types. The fate of the maternal proteome remains contested because indirect measurements cannot resolve it. Here, we combine 18O-water labeling with multiplexed proteomics to quantify protein turnover proteome-wide in frog and fly embryos. Through hatching, the frog preserves the bulk of its maternal proteome, confining rapid degradation to a small regulatory module. The fly cannot meet its synthesis demand from yolk alone and instead degrades nearly all maternal proteins, including housekeeping proteins long assumed stable, recycling them into new protein. Yet the turnover hierarchy is conserved, with disordered and regulatory proteins degrading fastest, while the fly rescales the whole proteome ~eightfold faster. These results recast the developmental proteome as both informational inheritance and metabolic reserve, establish 18O-water labeling as a turnover method for non-feeding organisms, and provide a resource of embryonic half-lives.

developmental biology↗

bioRxiv2025

Expanding Targeted Instrumentation for Discovery Applications: Complement Reporter Ion Quantification with a Quadrupole-Ion Trap Instrument

Proteomics workflows have traditionally been divided into discovery-based and targeted approaches, with instrumentation optimized specifically for each. Discovery experiments typically utilize high-resolution analyzers while targeted workflows rely on the sensitivity and specificity of triple quadrupole systems. Recently, a quadrupole-ion trap instrument (Stellar MS) demonstrated superior performance for targeted applications compared to conventional triple quadrupoles. In this study, we expand the capabilities of this platform to multiplexed shotgun proteomics using complement reporter ion quantification in an ion trap (iTMTproC). Benchmarking experiments with defined standards show that iTMTproC achieves quantification accuracy and interference reduction comparable to MultiNotch MS3 on the Orbitrap Fusion Lumos, a dedicated quadrupole-ion trap-Orbitrap tribrid instrument optimized for this purpose. Notably, iTMTproC quantifies slightly more proteins than MultiNotch MS3. We further validate this approach through a developmental time-series analysis of frog embryos, obtaining proteomic data nearly indistinguishable from MultiNotch MS3, with slightly increased protein quantification depth. These findings significantly extend the functionality of targeted instrumentation, underscoring the versatility of quadrupole-ion trap systems and providing cost-effective access to highly accurate, multiplexed quantitative shotgun proteomics.

systems biology↗

bioRxiv2024

Proteomic analysis of the pyrenoid-traversing membranes of Chlamydomonas reinhardtii reveals novel components

O_LIPyrenoids are algal CO2-fixing organelles that mediate approximately one-third of global carbon fixation. Most pyrenoids are traversed by membranes that are thought to supply them with concentrated CO2. Despite the critical nature of these membranes for pyrenoid function, they are poorly understood, with few protein components known in any species. C_LIO_LIHere, we identify protein components of the pyrenoid-traversing membranes from the leading model alga, Chlamydomonas reinhardtii, by affinity purification and mass spectrometry of membrane fragments. Our proteome includes previously-known proteins as well as novel candidates. C_LIO_LIWe further characterize two of the novel pyrenoid-traversing membrane-resident proteins: Cre10.g452250, which we name Pyrenoid Membrane Enriched 1 (PME1), and Cre02.g143550, also known as Low-CO2-Induced 16 (LCI16). We confirm the pyrenoid-traversing membrane localization of LCI16 and observe that PME1 and LCI16 physically interact. We find that neither protein is required for normal membrane morphology or growth under CO2-limiting conditions, but that both mutants show a similar proteomic profile to those of established pyrenoid mutants. C_LIO_LITaken together, our study identifies the proteome of the pyrenoid-traversing membranes and initiates the characterization of a novel pyrenoid-traversing membrane complex, building toward a mechanistic understanding of the pyrenoid. C_LI

molecular biology↗