Question: List interaction partners for the protein GATA1.

Context:
Our work describes, for the first time, distinct GATA-1 interactions with the essential hematopoietic factor Gfi-1b, the repressive MeCP1 complex, and the chromatin remodeling ACF/WCRF complex, in addition to the known GATA-1/FOG-1 and GATA-1/TAL-1 complexes. We also provide evidence that distinct GATA-1 complexes are associated with specific GATA-1 functions in erythroid differentiation, for example, GATA-1/Gfi-1b with the suppression of cell proliferation and GATA-1/FOG-1/MeCP1 with the repression of other hematopoietic transcription programs. We next applied the biotinylation tag to Ldb-1, a known partner of GATA-1, and characterized a number of novel interaction partners that are essential in erythroid development, in particular, Eto-2, Lmo4, and CdK9. 
Endogenous GATA1 and LDB1 proteins were confirmed to bind to LMO2-C by MBP pull down analysis. 
LMO2-C can bind endogenous GATA1 and LDB1 protein in K562 cells and down regulates the expression of GPA.
We identify novel transcription factor binding partners for PIAS3 including ETS, EGR1, NR1I2, and GATA1.
At other differentiation stages, additional combinatorial interactions occurred between RUNX1 and its coregulators, GATA1 and ETS. 
Ldb1, a ubiquitously expressed LIM domain binding protein, is essential in a number of tissues during development. It interacts with Gata1, Tal1, E2A and Lmo2 to form a transcription factor complex regulating late erythroid genes. 
Using a biotinylation tagging/proteomics approach in erythroid cells, we describe distinct GATA-1 interactions with the essential hematopoietic factor Gfi-1b, the repressive MeCP1 complex and the chromatin remodeling ACF/WCRF complex, in addition to the known GATA-1/FOG-1 and GATA-1/TAL-1 complexes. Importantly, we show that FOG-1 mediates GATA-1 interactions with the MeCP1 complex, thus providing an explanation for the overlapping functions of these two factors in erythropoiesis.
Here we show that Ski interacts with GATA1, a transcription factor essential in erythropoiesis. Using a Ski mutant deficient in GATA1 binding, we show that this Ski-GATA1 interaction is critical for Ski's ability to repress GATA1-mediated transcription and block erythroid differentiation. 
The zinc finger transcription factor GATA-1, a central mediator of erythroid gene expression, interacts with multiple proteins including FOG-1, EKLF, SP1, CBP/p300 and PU.1. 
tudies involving point mutants of GATA-1 have shown that a direct physical interaction between GATA-1 and FOG-1 is essential for normal human erythroid and megakaryocyte maturation in vivo. In addition, evidence has emerged that physical interaction between GATA-1 and the myeloid/lymphoid specific factor PU.1, an oncogene implicated in murine erythroleukemia, acts to functionally cross-antagonize one another. 

Answer: GATA-1 interact with factor Gfi-1b, the repressive MeCP1 complex, the chromatin remodeling ACF/WCRF complex, FOG-1, TAL-1, Ldb-1 and LMO2-C.
GATA1 interacts with the essential hematopoietic factor Gfi-1b, the repressive MeCP1 complex, the chromatin remodeling ACF/WCRF complex, in addition to the known GATA-1/FOG-1 and GATA-1/TAL-1 complexes. Ldb1 is a known partners of GATA1. LMO2-C can bind endogenous GATA1. Novel transcription factor binding partners for PIAS3 include GATA1. Combinatorial interactions occurre between RUNX1 and its coregulator GATA1. Ski interacts with GATA1. GATA-1 interacts with multiple proteins including FOG-1, EKLF, SP1, CBP/p300 and PU.1.
Exact answer: Gfi-1b, MeCP1, MeCP1 complex, ACF/WCRF complex, FOG-1, TAL-1, Ldb1, Ldb-1, LMO2-C, PIAS3, RUNX1, Ski, EKLF, SP1, CBP/p300, PU.1