biostudies-literaturePasquarelli RRDivision of Microbiology and Infectious Diseases, National Institute of Allergy and Infectious DiseasesNIAID NIH HHSMolecular Biology Institute, University of California, Los AngelesNational Institute of General Medical SciencesNIGMS NIH HHSe1012411https://www.ebi.ac.uk/biostudies/studies/S-EPMC11288415biostudies-literatureUnknown20(7)Toxoplasma gondii divides by endodyogeny, in which two daughter buds are formed within the cytoplasm of the maternal cell using the inner membrane complex (IMC) as a scaffold. During endodyogeny, components of the IMC are synthesized and added sequentially to the nascent daughter buds in a tightly regulated manner. We previously showed that the early recruiting proteins IMC32 and IMC43 form an essential daughter bud assembly complex which lays the foundation of the daughter cell scaffold in T. gondii. In this study, we identify the essential, early recruiting IMC protein BCC0 as a third member of this complex by using IMC32 as bait in both proximity labeling and yeast two-hybrid screens. We demonstrate that BCC0's localization to daughter buds depends on the presence of both IMC32 and IMC4PLoS pathogensBCC0 collaborates with IMC32 and IMC43 to form the Toxoplasma gondii essential daughter bud assembly complex.PMC11288415GM153408T32 GM007185R35 GM153408GM007185Whitcome Pre-doctoral FellowshipAI123360T32 AI007323R01 AI123360AI007323Sha JBradley PJPasquarelli RRWohlschlegel JAfalseBCC0 collaborates with IMC32 and IMC43 to form the Toxoplasma gondii essential daughter bud assembly complex.Toxoplasma gondii divides by endodyogeny, in which two daughter buds are formed within the cytoplasm of the maternal cell using the inner membrane complex (IMC) as a scaffold. During endodyogeny, components of the IMC are synthesized and added sequentially to the nascent daughter buds in a tightly regulated manner. We previously showed that the early recruiting proteins IMC32 and IMC43 form an essential daughter bud assembly complex which lays the foundation of the daughter cell scaffold in T. gondii. In this study, we identify the essential, early recruiting IMC protein BCC0 as a third member of this complex by using IMC32 as bait in both proximity labeling and yeast two-hybrid screens. We demonstrate that BCC0's localization to daughter buds depends on the presence of both IMC32 and IMC42024-01-01T00:00:00Z2024 Jul2026-03-31T11:05:01.769Z2025-08-27T03:11:23.3ZS-EPMC112884153902441110.1371/journal.ppat.1012411