is involved in regulating glucose levels and fatty acid secreted from adipose tissue, is modulated by site-specific phosphorylation of adiponectin by CK1δ. Parasitic CK1s hijack mammalian CK1 pathways Increasing evidence suggests that CK1 can be associated with infectious diseases by the manipulation of the CK1-related signaling pathways of the host cell by intracellular parasites, exporting their CK1 into the host cell. For Leishmania and Plasmodium, excreted CK1 contributes to reprogramming of the respective host cells. Possessing host functions parasitic CK1s are able to replace mammalian CK1s, thereby ensuring similar functions. Parasitic CK1s display a high level of identity towards human CK1δ TV1, suggesting that this human paralogue might be the preferred target for parasitic hijacking. The protein organization of parasitic CK1s is very similar to that of human CK1δ. All residues involved in ATP binding, the gatekeeper residue, as well as the DFG, KHD, and SIN motifs are generally conserved in parasitic CK1 sequences. This finding suggests, that they are crucial for CK1 function. However, the functions of these kinases in the parasites and more importantly their functions in the host cell are mainly unknown and remain to be investigated. CK1s from Plasmodium and Leishmania are most studied: The only CK1 in Plasmodium, PfCK1 (PF3D7_1136500), presents 69% of identity with human CK1 within the kinase domain and is essential for completion of the asexual intra-erythrocytic cycle. Similar to other CK1s, also PfCK1 has multiple binding partners and thus potentially regulates multiple pathways, including those regulating transcription, translation, and protein trafficking. Finally, PfCK1 seems to be essential for parasite proliferation in erythrocytes. From the six CK1 paralogues in Leishmania donovani only two paralogs, LdBPK_351020.1 and LdBPK_351030.1 (LmCK1.2), are closely related to human CK1. The only paralog described as having a function in the host cell. LdBPK_351030.1 is active in both promastigotes and amastigotes. LmCK1.2 can be inhibited by the CK1-specific inhibitor D4476 and is important for intracellular parasite survival. So far, only few substrates for LmCK1.2 have been identified and the functions of LmCK1.2 in the parasite are poorly studied. Although LmCK1.2 is highly identic to human CK1, several small molecules have been identified to specifically target Leishmania CK1, thereby providing opportunities for new therapeutic strategies. Modulating CK1δ activity Due to the fact that CK1δ is involved in regulation of various cellular processes there is high attempts to influence its activity. Since changes of the expression and/or activity as well as