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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Unlike mammalian and yeast cells, little is known about how plants regulate G1 progression and entry into the S phase of the cell cycle. In mammalian cells, a key regulator of this process is the retinoblastoma tumor suppressor protein (RB). In contrast, G1 control in Saccharomyces cerevisiae does not utilize an RB-like protein. We report here the cloning of cDNAs from two Zea mays genes, RRB1 and RRB2, that encode RB-related proteins. Further, RRB2 transcripts are alternatively spliced to yield two proteins with different C termini. At least one RRB gene is expressed in all the tissues examined, with the highest levels seen in the shoot apex. RRB1 is a 96-kDa nuclear protein that can physically interact with two mammalian DNA tumor virus oncoproteins, simian virus 40 large-T antigen and adenovirus E1A, and with a plant D-type cyclin. These associations are abolished by mutation of a conserved cysteine residue in RRB1 that is also essential for RB function. RRB1 binding potential is also sensitive to deletions in the conserved A and B domains, although differences exist in these effects compared to those of human RB. RRB1 can also bind to the AL1 protein from tomato golden mosaic virus (TGMV), a protein which is essential for TGMV DNA replication. These results suggest that G1 regulation in plant cells is controlled by a mechanism which is much more similar to that found in mammalian cells than that in yeast.
Mol Cell Biol 1997 Sep
PMID:RRB1 and RRB2 encode maize retinoblastoma-related proteins that interact with a plant D-type cyclin and geminivirus replication protein. 927 85

Ribosome biogenesis is regulated by environmental cues that coordinately modulate the synthesis of ribosomal components and their assembly into functional subunits. We have identified an essential yeast WD-repeat-containing protein, termed Rrb1p, that has a role in both the assembly of the 60S ribosomal subunits and the transcriptional regulation of ribosomal protein (RP) genes. Rrb1p is located in the nucleus and is concentrated in the nucleolus. Its presence is required to maintain normal cellular levels of 60S subunits, 80S ribosomes, and polyribosomes. The function of Rrb1p in ribosome biogenesis appears to be linked to its association with the ribosomal protein rpL3. Immunoprecipitation of Rrb1p from nuclear extracts revealed that it physically interacts with rpL3. Moreover, the overproduction of Rrb1p led to increases in cellular levels of free rpL3 that accumulated in the nucleus together with Rrb1p. The concentration of these proteins within the nucleus was dependent on ongoing protein translation. We also showed that overexpression of RRB1 led to an increase in the expression of RPL3 while all other examined RP genes were unaffected. In contrast, depletion of RRB1 caused an increase in the expression of all RP genes examined except RPL3. These results suggest that Rrb1p regulates RPL3 expression and uncouples it from the coordinated expression of other RP genes.
Mol Cell Biol 2001 Feb
PMID:Rrb1p, a yeast nuclear WD-repeat protein involved in the regulation of ribosome biosynthesis. 1115 12

Phage display procedure was applied to the N-terminal domain of human topoisomerase I. The consensus sequence identified for clones binding to the N-terminal domain was found in 35 human proteins that are either permanently or temporarily located in the nucleus. They are in majority involved in the DNA repair, transcription, RNA metabolism or cell cycle control. Four of identified proteins: Bub3 protein, Cockayne syndrome protein A, damaged DNA binding protein 2 and GRWD protein belong to WD-repeat proteins and their sequences recognized by the N-terminal domain are identically localized.
Mol Biol Rep 2002 Dec
PMID:Potential protein partners for the N-terminal domain of human topoisomerase I revealed by phage display. 1254 20

In mammalian cells, Cdt1 activity is strictly controlled by multiple independent mechanisms, implying that it is central to the regulation of DNA replication during the cell cycle. In fact, unscheduled Cdt1 hyperfunction results in rereplication and/or chromosomal damage. Thus, it is important to understand its function and regulations precisely. We sought to comprehensively identify human Cdt1-binding proteins by a combination of Cdt1 affinity chromatography and liquid chromatography and tandem mass spectrometry analysis. Through this approach, we could newly identify 11 proteins, including subunits of anaphase-promoting complex/cyclosome (APC/C), SNF2H and WSTF, topoisomerase I and IIalpha, GRWD1/WDR28, nucleophosmin/nucleoplasmin, and importins. In vivo interactions of Cdt1 with APC/C(Cdh1), SNF2H, topoisomerase I and IIalpha, and GRWD1/WDR28 were confirmed by coimmunoprecipitation assays. A further focus on APC/C(Cdh1) indicated that this ubiquitin ligase controls the levels of Cdt1 during the cell cycle via three destruction boxes in the Cdt1 N-terminus. Notably, elimination of these destruction boxes resulted in induction of strong rereplication and chromosomal damage. Thus, in addition to SCF(Skp2) and cullin4-based ubiquitin ligases, APC/C(Cdh1) is a third ubiquitin ligase that plays a crucial role in proteolytic regulation of Cdt1 in mammalian cells.
Mol Biol Cell 2008 Mar
PMID:Identification of novel human Cdt1-binding proteins by a proteomics approach: proteolytic regulation by APC/CCdh1. 1816 79