The 8-kDa Dynein Light Chain Binds to p53-binding Protein 1 and Mediates DNA Damage-induced p53 Nuclear Accumulation

Abstract

The tumor suppressor protein p53 is known to undergo cytoplasmic dynein-dependent nuclear translocation in response to DNA damage. However, the molecular link between p53 and the minus end-directed microtubule motor dynein complex has not been described. We report here that the 8-kDa light chain (LC8) of dynein binds to p53-binding protein 1 (53BP1). The LC8-binding domain was mapped to a short peptide segment immediately N-terminal to the kinetochore localization region of 53BP1. The LC8-binding domain is completely separated from the p53-binding domain in 53BP1. Therefore, 53BP1 can potentially act as an adaptor to assemble p53 to the dynein complex. Unlike other known LC8-binding proteins, 53BP1 contains two distinct LC8-binding motifs that are arranged in tandem. We further showed that 53BP1 can directly associate with the dynein complex. Disruption of the interaction between LC8 and 53BP1 in vivo prevented DNA damageinduced nuclear accumulation of p53. These data illustrate that LC8 is able to function as a versatile acceptor to link a wide spectrum of molecular cargoes to the dynein motor.

Dynein Light Chain Association Sequences Can Facilitate Nuclear Protein Import

“…As can be seen in Figure 4A (single transfection), the GFP-DLC-AS showed subcellular distributions not distinguishable from that of GFP alone (compare with Figure 2A); image analysis confirmed that the nuclear accumulation by both GFP-DLC-ASs was not increased compared with GFP alone (not shown). We confirmed that p53BP1 1117-1177 could associate with LC8 (Lo et al, 2005) by coexpression with dsRed-LC8, which resulted in colocalization in the cytoplasm ( Figure 4A, dual transfection). PTHR 478-511 did not colocalize with dsRed-LC8, as it is a DLC-AS for the light-chain Tctex-1 (Sugai et al, 2003; Figure 4A, dual transfection).…”

“…To test the ability of DLC-ASs from alternative sources (PTHR residues 478-511 and p53BP1 residues 1117-1177; Sugai et al, 2003;Lo et al, 2005) to facilitate nuclear import, we cloned the relevant sequences downstream of GFP and expressed the proteins in COS-7 cells. As can be seen in Figure 4A (single transfection), the GFP-DLC-AS showed subcellular distributions not distinguishable from that of GFP alone (compare with Figure 2A); image analysis confirmed that the nuclear accumulation by both GFP-DLC-ASs was not increased compared with GFP alone (not shown).…”

“…Although the sequences responsible for p53, PTHrP, and Rb interaction with MTs/dynein remain largely undefined, short sequences from several other proteins have been identified, using the yeast two-hybrid system and proteomics approaches, which confer interaction with the dynein light chains (DLC), LC8 and Tctex-1. These sequences variously include the consensus motifs KSTQT (single letter amino acid code) and GIQVD for LC8, as well as less well-defined motifs for Tctex-1 interaction, including SKCSR (Raux et al, 2000;Alonso et al, 2001;Poisson et al, 2001;RodriguezCrespo et al, 2001;Mueller et al, 2002;Martinez-Moreno et al, 2003;Sugai et al, 2003;Lo et al, 2005). DLC-ASs have been suggested to mediate cargo association with dynein motor complexes to effect nuclear targeting, so that they could potentially be exploited for delivery of therapeutics to This article was published online ahead of print in MBC in Press (http://www.molbiolcell.org/cgi/doi/10.1091/mbc.E07-01-0030) on June 13, 2007. cell nuclei (Cohen et al, 2005;Mastrobattista et al, 2006a,b); however, this has never been directly demonstrated.…”

Dynein light chain 1 is required for autophagy, protein clearance, and cell death inDrosophila

“…Discussion Drosophila ddlc1 is required for cell death of salivary glands. Ddlc1 has been implicated in the regulation of cell death through physical interactions with Bim (21) and p53 binding protein (37). In these cases, Ddlc1 restricts the activity of caspase regulators and caspases.…”

The dynein light chain 8 binding motif of rabies virus phosphoprotein promotes efficient viral transcription

“…Previous studies indicate that the interaction of LC8 and the transcription factor tricho-rhino-phalangeal syndrome 1 releases its suppressor activity to promote the transcription of GATA consensus sequences (18). Likewise, the interaction of LC8 with P53 binding protein 1 regulates the nuclear distribution of p53-binding protein 1 and p53 (19). In fact, LC8 binds to several transcription factors, including nuclear respiratory factor 1 (20) and Drosophila swallow (21).…”