InterPro domain: IPR037912

Microspherule protein 1 (MCRS1 or MSP58) is an RNA-binding protein that interacts with Daxx transcriptional regulator, relieving its repressor activity. Overexpression of MCRS1 leads to translocation of Daxx to the enlarged nucleoli in COS-1 or 293 cells [ 1 ]. It also interacts with fragile X mental retardation protein (FMRP), which represses specific mRNAs being transported as silent ribonucleoparticles from the cell body of a neuron to the distant synapse. MCRS1 binds to the G-quadruplex structures of the mRNA [ 2 ]. MCRS1 is a component of the NSL complex [ 3 ], the MLL1/MLL complex [ 4 ], and is a putative regulatory component in the chromatin remodeling INO80 complex [ 5 ]. The isoform MCRS2 is a cell-cycle-dependent protein which accumulates in the early S phase, and interacts with the telomerase-inhibitory protein LPTS/PinX1 [ 6 ].

1. Essential role of the 58-kDa microspherule protein in the modulation of Daxx-dependent transcriptional repression as revealed by nucleolar sequestration. J. Biol. Chem. 277, 25446-56
2. The nuclear microspherule protein 58 is a novel RNA-binding protein that interacts with fragile X mental retardation protein in polyribosomal mRNPs from neurons. Hum. Mol. Genet. 15, 1525-38
3. Subunit composition and substrate specificity of a MOF-containing histone acetyltransferase distinct from the male-specific lethal (MSL) complex. J. Biol. Chem. 285, 4268-72
4. Physical association and coordinate function of the H3 K4 methyltransferase MLL1 and the H4 K16 acetyltransferase MOF. Cell 121, 873-85
5. Subunit organization of the human INO80 chromatin remodeling complex: an evolutionarily conserved core complex catalyzes ATP-dependent nucleosome remodeling. J. Biol. Chem. 286, 11283-9
6. Human MCRS2, a cell-cycle-dependent protein, associates with LPTS/PinX1 and reduces the telomere length. Biochem. Biophys. Res. Commun. 316, 1116-23