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LC8 dynein light chain (DYNLL1) binds to the C-terminal domain of ATM-interacting protein (ATMIN/ASCIZ) and regulates its subcellular localization

Author:
Rapali, Péter, García-Mayoral, María Flor, Martínez-Moreno, Mónica, Tárnok, Krisztián, Schlett, Katalin, Albar, Juan Pablo, Bruix, Marta, Nyitray, László, Rodriguez-Crespo, Ignacio
Source:
Biochemical and biophysical research communications 2011 v.414 no.3 pp. 493-498
ISSN:
0006-291X
Subject:
DNA damage, amino acids, dynein ATPase, gel chromatography, heart, humans, microtubules, molecular weight, nuclear magnetic resonance spectroscopy, polypeptides, two hybrid system techniques, viral proteins
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 400kDa 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.
Agid:
894752