The function of CFAP45 (cilia and flagella associated protein 45, Ensembl gene identifier ENSG00000213085) is as follows. Microtubule inner protein (MIP) part of the dynein-decorated doublet microtubules (DMTs) in cilia axoneme, which is required for motile cilia beating (PubMed:36191189). It is an AMP-binding protein that may facilitate dynein ATPase-dependent ciliary and flagellar beating via adenine nucleotide homeostasis. May function as a donor of AMP to AK8 and hence promote ADP production (PubMed:33139725). {ECO:0000250|UniProtKB:Q32LN4, ECO:0000269|PubMed:33139725, ECO:0000269|PubMed:36191189}.