{"doi":"10.1093/genetics/iyaf020","title":"The Rac1 homolog CED-10 is a component of the MES-1/SRC-1 pathway for asymmetric division of the <i>Caenorhabditis elegans</i> EMS blastomere","abstract":"Asymmetric cell division is essential for the creation of cell types with different identities and functions. The endomesodermal precursor cell (EMS) of the 4-cell Caenorhabditis elegans embryo undergoes an asymmetric division in response to partially redundant signaling pathways. One pathway involves a Wnt signal from the neighboring P2 cell, while the other pathway is defined by the receptor-like MES-1 transmembrane protein localized at the EMS-P2 cell contact and the cytoplasmic kinase SRC-1. In response to these signals, the EMS nuclear-centrosome complex rotates, so that the spindle forms on the anterior-posterior axis; after division, the daughter cell contacting P2 becomes the endodermal precursor cell. Here, we identify the Rac1 homolog CED-10 as a new component of the MES-1/SRC-1 pathway. Loss of CED-10 affects both spindle positioning and endoderm specification in the EMS cell. SRC-1 dependent phosphorylation at the EMS-P2 contact is reduced. However, the asymmetric division of the P2 cell, which is also MES-1 and SRC-1 dependent, appears normal in ced-10 mutants. These and other results suggest that CED-10 acts upstream of, or at the level of, SRC-1 activity in the EMS cell. In addition, we find that the branched actin regulator ARX-2 is enriched at the EMS-P2 cell contact site, in a CED-10-dependent manner. Loss of ARX-2 results in EMS spindle orientation defects, suggesting that CED-10 acts through branched actin to promote spindle orientation in the EMS cell.","journal":"Genetics","year":2025,"id":551456,"datarank":0.0,"base_score":0.0,"endowment":0.0,"self_citation_contribution":0.0,"citation_network_contribution":0.0,"self_endowment_contribution":0.0,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":1,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9513,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2025-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":1336184,"name":"McKenzi Fernholz","orcid":null,"position":1,"is_corresponding":false},{"id":1335878,"name":"Małgorzata J Liro","orcid":"0000-0002-7481-9065","position":2,"is_corresponding":false},{"id":809935,"name":"Krista M Myles","orcid":"0000-0002-1281-7793","position":3,"is_corresponding":false},{"id":1335879,"name":"Holly E. Anderson","orcid":"0009-0006-9721-0048","position":4,"is_corresponding":false},{"id":999085,"name":"Lesilee S. Rose","orcid":"0000-0003-4611-9704","position":5,"is_corresponding":false},{"id":574995,"name":"Helen Lamb","orcid":"0000-0002-4425-7014","position":0,"is_corresponding":true}],"reference_count":61,"raw_metadata":null,"created_at":"2026-07-19T02:54:25.065895Z","pmid":"39891664","pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}