Disease relevance of HNRPUL1

• Gene variants of VAMP8 and HNRPUL1 are associated with early-onset myocardial infarction [1].
• Immunoprecipitation experiments indicate that two distinct segments in the 55-kDa polypeptide which partly overlap regions responsible for p53 binding are required for complex formation with E1B-AP5 in Ad-infected cells and that this protein interaction is modulated by the adenovirus E4orf6 protein [2].

High impact information on HNRPUL1

• The E1B-AP5 gene encodes a novel nuclear RNA-binding protein of the heterogeneous nuclear ribonucleoprotein (hnRNP) family that is highly related to hnRNP-U/SAF-A [2].
• These data suggest that E1B-AP5 might play a role in RNA transport and that this function is modulated by E1B-55kDa in Ad-infected cells [2].
• Disruption of the E1B-AP5-BRD7 complex increased E1B-AP5 repression activity for basic transcription and converted it from being an activator of the hormone-dependent promoter into being a strong repressor [3].
• By in situ immunofluorescence we demonstrated that E1B-AP5 co-localizes with the nuclear fraction of HRMT1L1 [4].
• The activity responsible for E1B-AP5 methylation forms a complex with E1B-AP5 in vivo [4].

Chemical compound and disease context of HNRPUL1

• Arginine methylation of Ad (adenovirus) E1B 55-kDa-associated protein E1B-AP5 was recently described by us [Kzhyshkowska, Schutt, Liss, Kremmer, Stauber, Wolf and Dobner (2001) Biochem. J. 358, 305-314] [5].

Biological context of HNRPUL1

• A novel mammalian hnRNP, E1B-AP5, recently identified by its interaction with adenovirus early protein E1B-55 kDa, has been proposed to have a regulatory role in adenoviral and host-cell mRNA processing/nuclear export [Gabler, Schutt, Groitl, Wolf, Shenk and Dobner (1998) J. Virol. 72, 7960-7971] [4].
• The Src homology 3 (SH3) domain of HRMT1L1 was essential for its interaction with E1B-AP5 in vivo [4].
• The binding site for E1B-AP5 has been mapped to the C-terminal region of p53 [6].
• Transfection of E1B-AP5 into human tumour cells affected the cellular response to UV radiation, such that, although p53 expression was induced, little change in the level of p53-inducible genes could be observed [6].

Associations of HNRPUL1 with chemical compounds

• In this first example of protein arginine methylation analysis in Ad-infected cells, we investigated methylation of the E1B-AP5 and the viral L4-100 kDa protein [5].

Physical interactions of HNRPUL1

• Using yeast two-hybrid screening we identified HRMT1L1 (PRMT2) as one of the proteins interacting with E1B-AP5 [4].

Regulatory relationships of HNRPUL1

• In reporter assays, E1B-AP5 inhibited p53 transcriptional activity although not as efficiently as the Ad5E1B55K protein [6].

Other interactions of HNRPUL1

• We confirmed E1B-AP5-BRD7 complex formation in vivo and in vitro [3].
• We suggest that HRMT1L1 is responsible for specific E1B-AP5 methylation in vivo [4].
• Finally, we show that TAP interacts with transportin and with two proteins implicated in the export of cellular mRNAs: RAE1/hGle2 and E1B-AP5 [7].
• The interaction of the hnRNP family member E1B-AP5 with p53 [6].

References