Platelets are anucleate and traditionally considered incapable of nuclear functions. In contrast to this preconceived notion, we and others were able to detect nuclear proteins in human platelets. Nevertheless, for most of these proteins it is unclear if traditional nuclear or alternatively assigned functions are performed. In this work, nucleoseome-assembly-protein-1-like-1 (NAP1L1), a representative of a large protein family whose members share the ability to facilitate nucleosome (dis-)assembly on DNA templates, was unequivocally shown to be present in human platelets and their progenitor cells (CD34+ hematopoietic stem cells and megakaryocytes) in three different isoforms (60 kDa, 53 kDa und 37 kDa -NAP1L1-Isoform). Alternative functions have been described for NAP1 family members, including chaperone functions, but to date there is no report in the literature describing the expression of NAP1L1 or its function in human platelets or their progenitor cells. In our analysis we identified and verified dihydrolipoyllysine-residue acetyltransferase (DLAT, syn.: PDC-E2) by combined co-IP and LC-MS/MS approach as interaction partner of NAP1L1. The protein plays a crucial role in maintaining cellular respiration and energy production by linking glycolysis with the citric acid cycle and therefore promoting ATP-synthesis via the respiratory chain. It is important to note that platelets are highly dependent on a functional cellular respiration which defines them as indicators for ...