title: LC8 dynein light chain (DYNLL1) binds to the C-terminal domain of ATM-interacting protein (ATMIN/ASCIZ) and regulates its subcellular localization.
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.
authors.affiliation: Dept. Biochemistry, Eötvös Loránd University, Budapest, Hungary.
authors.forename: Péter
authors.initials: P
authors.lastname: Rapali
authors.forename: María Flor
authors.initials: MF
authors.lastname: García-Mayoral
authors.forename: Mónica
authors.initials: M
authors.lastname: Martínez-Moreno
authors.forename: Krisztián
authors.initials: K
authors.lastname: Tárnok
authors.forename: Katalin
authors.initials: K
authors.lastname: Schlett
authors.forename: Juan Pablo
authors.initials: JP
authors.lastname: Albar
authors.forename: Marta
authors.initials: M
authors.lastname: Bruix
authors.forename: László
authors.initials: L
authors.lastname: Nyitray
authors.forename: Ignacio
authors.initials: I
authors.lastname: Rodriguez-Crespo
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D056445:Cytoplasmic Dyneins / Q000378:metabolism*; D006801:Humans; D042541:Intracellular Space / Q000378:metabolism; D008969:Molecular Sequence Data; D019906:Nuclear Magnetic Resonance, Biomolecular; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D017434:Protein Structure, Tertiary / Q000235:genetics; D014157:Transcription Factors; D020798:Two-Hybrid System Techniques
chemical_list: C522841:ATMIN protein, human; D002352:Carrier Proteins; D009687:Nuclear Proteins; D014157:Transcription Factors; C427758:DYNLL1 protein, human; D056445:Cytoplasmic Dyneins