The Cdc42 effector and non-receptor tyrosine kinase, ACK defines a distinct STAT5 transcription signature in a chronic myeloid leukaemia cell model

Activated Cdc42-associated kinase (ACK) is a Rho family effector that is widely implicated in cancer. Here, we describe new roles for ACK in transcriptional regulation mediated by its relationship with the signal transducer and activators of transcription (STAT) family. We show that ACK can interact with STAT3, STAT5A and STAT5B, and augments phosphorylation at the conserved activation tyrosine on these STAT members. ACK stimulates oncogenic STAT nuclear relocation and transcriptional activation. We also identify endogenous relationships between ACK and STAT family members in haematopoietic disease cell lines. In the K562 chronic myeloid leukaemia cell line, we confirm that ACK contributes to the pool of active, nuclear STAT5. By interrogating ACK knock out cells we describe an ACK-driven STAT5 transcriptional signature in K562s. We propose ACK as a contributor to hyperactivated STAT5 signalling in this CML cell line and reveal a new route for therapeutic intervention. ### Competing Interest Statement The authors have declared no competing interest.