LC8 Dynein Light Chain (DYNLL1) Binds to the C-terminal Domain of ATM-interacting Protein (ATMIN/ASCIZ) and Regulates Its Subcellular Localization

Biochem Biophys Res Commun. 2011 Oct 28;414(3):493-8. doi: 10.1016/j.bbrc.2011.09.093. Epub 2011 Sep 24.

Abstract

LC8 dynein light chain (now termed DYNLL1 and DYNLL2 in mammals), a dimeric 89 amino acid protein, is a component of the dynein multi-protein complex. However a substantial amount of DYNLL1 is not associated to microtubules and it can thus interact with dozens of cellular and viral proteins that display well-defined, short linear motifs. Using DYNLL1 as bait in a yeast two-hybrid screen of a human heart library we identified ATMIN, an ATM kinase-interacting protein, as a DYNLL1-binding partner. Interestingly, ATMIN displays at least 18 SQ/TQ motifs in its sequence and DYNLL1 is known to bind to proteins with KXTQT motifs. Using pepscan and yeast two-hybrid techniques we show that DYNLL1 binds to multiple SQ/TQ motifs present in the carboxy-terminal domain of ATMIN. Recombinant expression and purification of the DYNLL1-binding region of ATMIN allowed us to obtain a polypeptide with an apparent molecular mass in gel filtration close to 400 kDa that could bind to DYNLL1 in vitro. The NMR data-driven modelled complexes of DYNLL1 with two selected ATMIN peptides revealed a similar mode of binding to that observed between DYNLL1 and other peptide targets. Remarkably, co-expression of mCherry-DYNLL1 and GFP-ATMIN mutually affected intracellular protein localization. In GFP-ATMIN expressing-cells DNA damage induced efficiently nuclear foci formation, which was partly impeded by the presence of mCherry-DYNLL1. Thus, our results imply a potential cellular interference between DYNLL1 and ATMIN functions.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Binding Sites
  • Carrier Proteins / genetics
  • Carrier Proteins / metabolism*
  • Cytoplasmic Dyneins / metabolism*
  • Humans
  • Intracellular Space / metabolism
  • Molecular Sequence Data
  • Nuclear Magnetic Resonance, Biomolecular
  • Nuclear Proteins / genetics
  • Nuclear Proteins / metabolism*
  • Protein Structure, Tertiary / genetics
  • Transcription Factors
  • Two-Hybrid System Techniques

Substances

  • ATMIN protein, human
  • Carrier Proteins
  • Nuclear Proteins
  • Transcription Factors
  • DYNLL1 protein, human
  • Cytoplasmic Dyneins