This entry carries part of the crucial 144 N-terminal residues of the FmiP (Fms interacting protein). A member of the THO (suppressors of the transcriptional defects of hpr1delta by overexpression) complex which is a subcomplex of the transcription/export (TREX) complex [1]. It is essential for the binding of the protein to the cytoplasmic domain of activated Fms-molecules in M-CSF induced haematopoietic differentiation of macrophages. Fmip is also known as THOC5 (THO complex subunit 5) a 683 amino acids long protein which contains a nuclear localisation sequence (NLS), a leucine zipper and a PEST like sequence (aa. 303-319) that carries three ataxia-telangiectasia mutated (ATM) kinase specific phosphorylation sites. The C-terminus contains a THOC1 binding site [2]. The level of FMIP/Thoc5 expression might form a threshold that determines whether cells differentiate into macrophages or into granulocytes [3].

1: THOC5/FMIP, an mRNA export TREX complex protein, is essential for hematopoietic primitive cell survival in vivo. Mancini A, Niemann-Seyde SC, Pankow R, El Bounkari O, Klebba-Farber S, Koch A, Jaworska E, Spooncer E, Gruber AD, Whetton AD, Tamura T; BMC Biol. 2010;8:1. PMID:20051105

2: An ataxia-telangiectasia-mutated (ATM) kinase mediated response to DNA damage down-regulates the mRNA-binding potential of THOC5. Ramachandran S, Tran DD, Klebba-Faerber S, Kardinal C, Whetton AD, Tamura T; RNA. 2011;17:1957-1966. PMID:21937706

3: FMIP, a novel Fms-interacting protein, affects granulocyte/macrophage differentiation. Tamura T, Mancini A, Joos H, Koch A, Hakim C, Dumanski J, Weidner KM, Niemann H; Oncogene. 1999;18:6488-6495. PMID:10597251