## 2 Results and Discussion
### Gene Ontology Enrichment Analyses of PbPP1c-Interacting Proteins
STRING analysis of this pathway showed a very high degree of interaction among these proteins (>1400 associations, not shown). Interestingly, phosphorylation is known to be a central mechanism for translational control in mammals, and a role of PP1c in the dephosphorylation of eiF2\(\alpha\) to restore translational process upon cell stress has been reported [27]. In addition, eiF2\(\beta\), which was found in the PP1c interactome in this study but at the limit of significance and also in a recent report [15], was confirmed as a direct interactor of PP1c both in mammals and in _Plasmodium_[28, 29]. In gametocytes, the GO analysis of PbPP1c-interacting proteins identified 28 pathways as significantly enriched (Supplementary Materials Table S2). Pathways with the highest fold enrichment included spliceosomal SnRNP assembly, microtubule-based movement, microtubule-based processes, movement of cell and DNA replication. When annotations from the full GO terms were converted to GO Slim, PbPP1c was found to cluster with two main pathways (Table 2), including the \"cellular component assembly\" pathway, which is also observed in schistors. STRING analysis of the 27 proteins of this pathway showed an additional network in gametocytes, when compared with schizont stages, corresponding to microtubule-associated proteins (Figure 4). Four proteins with no associations with other proteins of the network were removed from the Cytoscape visualization. They included the radial spoke head protein (PBANKA_0942300) and armadillo repeat protein PF16 (PBANKA_0917400): two proteins that are associated with the axoneme and flagella. Of note, the PbPP1c interactome in gametocytes also included kinesin 13 and kinesin 15, together with 14 putative dynein chains, confirming the overall enrichment in microtubule-based processes (Supplementary Materials Table S1). These data are supported by a recent report showing a cyclic accumulation of PbPP1c at the kinetochore during gametogony, suggesting a role for PP1 in regulating mitotic entry and exit [15]. Moreover, several microtubule proteins known to be associated with the spindle or axoneme, some of which were also found in our study, were pulled down with PP1c in gametocytes. The other GO Slim pathway specifically enriched in the PbPP1c interactome in gametocytes was related to protein transport and encompassed 24 proteins (Table 2). The constructed functional protein association network showed 20 nodes and 69 edges, which is a strong enrichment in terms of functional associations when compared to a random network (Figure 5). Few of these proteins belong to significantly enriched KEGG pathways. However, manual inspection based both on PlasmoDB protein description and the literature allowed the identification of three highly interconnected sub-complexes: Clathrin-associated adaptor protein complex (AP-1 complex), coat protein complexes (COPI or coatomer, and COPII), and Sec machinery (or translocase). AP-1 plays a role in protein sorting in the late-Golgi/trans-Golgi network and/or endosomes. It mediates both the recruitment of clathrin to membranes and the recognition of sorting signals within the cytosolic tails of transmembrane cargo molecules. In _Plasmodium_, it has been suggested that AP-1, and especially its ul subunit, was involved in rhoptry protein trafficking [30]. Coat protein complexes are non clathrin-based complexes involved in the transport of proteins