Biology subjects

Clutario, K. M.

Publications and source records attributed to Clutario, K. M..

2 recordsLinked to original sources

bioRxiv2025

Human REXO4 is Required for Cell Cycle Progression

Human REXO4 is a poorly characterized exonuclease that is overexpressed in human cancers. To better understand the function of REXO4 and its relationship to cellular proliferation, we have undertaken multidisciplinary approaches to characterize its cell cycle phase-dependent subcellular localization and the cis determinants required for this localization, its importance to cell cycle progression and cell viability, its protein-protein association network, and its activity. We show that the localization of REXO4 to the nucleolus in interphase depends on an N-terminal nucleolar localization sequence and that its localization to the perichromosomal layer of mitotic chromosomes is dependent on Ki67. Depletion of REXO4 led to a G1/S cell cycle arrest, and reduced cell viability. REXO4 associated with ribosome components and other proteins involved in rRNA metabolism. We propose a model where REXO4 is important for proper rRNA processing, which is required for ribosome biogenesis, cell cycle progression, and proliferation. SIGNIFICANCE STATEMENTO_LIREXO4 is a putative RNA exonuclease with limited characterization. The authors used in silico, cell, and molecular biology approaches to characterize its localization, associations, regulation, and function. C_LIO_LIThey found that during interphase, REXO4 localizes to the nucleolus through an N-terminal nucleolar localization sequence. Whereas during mitosis, REXO4 localized to the perichromosomal layer in a Ki67-dependent manner. REXO4 was required for proper cell cycle progression, and viability. C_LIO_LIThese results indicated that REXO4 is important for regulating cell proliferation. C_LI

cell biology↗

bioRxiv2020

Dissection of the Spindle Assembly Checkpoint by Proximity Proteomics

The spindle assembly checkpoint (SAC) is critical for sensing defective microtubule-kinetochore attachments and tension across the kinetochore and functions to arrest cells in prometaphase to allow time to repair any errors prior to proceeding into anaphase. The SAC has a central role in ensuring the fidelity of chromosome segregation and its dysregulation has been linked to the development of human diseases like cancer. The establishment and maintenance of the SAC relies on multiple protein complexes that are intricately regulated in a spatial and temporal manner through posttranslational modifications like phosphorylation. Over the past few decades the SAC has been highly investigated and much has been learned about its protein constituents and the pathways and factors that regulate its activity. However, the spatio-temporal proximity associations of the core SAC components have not been explored in a systematic manner. Here, we have taken a BioID2 proximity-labeling proteomic approach to define the proximity protein environment for each of the five core SAC proteins BUB1, BUB3, BUBR1, MAD1L1, and MAD2L1 under conditions where the SAC is active in prometaphase. These five protein association maps were integrated to generate the SAC proximity protein network that contains multiple layers of information related to core SAC protein complexes, protein-protein interactions, and proximity associations. Our analysis validated many of the known SAC complexes and protein-protein interactions. Additionally, it uncovered new protein associations that lend insight into the functioning of the SAC and highlighted future areas that should be investigated to generate a comprehensive understanding of the SAC.

biochemistry↗