Heat shock protein (Hsp) 70 and Hsp90 are an evolutionarily conserved class of molecular chaperones and are major contributors to the maintenance of protein homeostasis. They fold nascent and misfolded proteins called “clients” and they collaborate with other proteins, called co-chaperones. One of these co-chaperones is the Hsp70-Hsp90 organizing protein (Hop) which is only found in eukaryotic cells. Hop interacts with Hsp70 and Hsp90 to form the Hsp70-Hop-Hsp90 ternary complex. An upregulation or overexpression of Hop is positively correlated with several cancers. In this work, we investigated whether Hop is an oncoprotein. We could not verify nor disprove an implication of Hop in cancer in isogenic pairs of normal and oncogenically transformed RPE1 cells by Hop knock-down (KD). Also, our preliminary results showed that Hop KD in normal RPE1 cells renders them resistant to Hsp90 inhibition whereas this is not the case for transformed RPE1 cells. Hop is also prone to post-translational modifications such as phosphorylation. Here we showed that Hop mutants with the phosphomimic (Y354E) and the non-phosphorylatable (Y354F) form of tyrosine 354 (Y354) exhibit weaker interactions with Hsp70 and Hsp90 isoforms compared to Hop WT. Even though we could not identify the kinase responsible for the phosphorylation of Y354, we showed that the association of the Hsp90 client and tyrosine kinase c-Abl with the ternary complex is increased in presence of Y354E Hop and Y354F Hop and that its activation is halved in presence of Y354E Hop. Taken together, our data suggest that substitutions of Y354 may lead to a slowdown in the transfer and the activation of c-Abl.