Non-receptor tyrosine-protein and serine/threonine-protein kinase that is implicated in diverse biological functions such as cell survival, cell differentiation, cell growth and proliferation (PubMed:11997505, PubMed:18816840, PubMed:22615583, PubMed:23562806, PubMed:25223282, PubMed:27462444). Phosphorylates SH3PX1 and ex (PubMed:22615583, PubMed:11773052, PubMed:27462444). Phosphorylates SH3PX1 predominantly on 'Tyr-56', which likely promotes the recruitment of SH3PX1 to an axonal guidance receptor complex that includes dock and Dscam; because phosphorylation of SH3PX1 increases its interaction with the complex member dock while decreasing its interaction with the actin cytoskeleton modulator WASp (PubMed:11773052). In the wing and eye, promotes tissue growth, and during embryogenesis coordinates cell shape changes required for correct dorsal closure (PubMed:22615583, PubMed:27462444, PubMed:18816840). Functions in the negative regulation of the Hippo/SWH (Sav/Wts/Hpo) signaling pathway by enhancing yki activity thereby promoting cell proliferation and inhibiting apoptosis (PubMed:22615583, PubMed:27462444). This is accomplished, at least in part, by phosphorylating ex thereby reducing its ability to efficiently activate the Hippo signaling cascade (PubMed:27462444). In the eye disk, wing disk and possibly spermatids, inhibits programmed cell death induced by hid and rpr through a mechanism that is independent of the MAP kinase signal transduction pathway (PubMed:22615583). Essential for male and female fertility (PubMed:22615583, PubMed:23562806). During oogenesis required for the correct temporal assembly, and consequently the catalytic activity of long CTPsyn filaments (cytoophidium) in the germline nurse cells, likely by phosphorylating an unidentified substrate that is essential for linking individual CTPsyn filaments into large, catalytically active assemblies (PubMed:25223282). ATP + L-tyrosyl-[protein] = ADP + H(+) + O-phospho-L-tyrosyl-[protein] ATP + L-threonyl-[protein] = ADP + H(+) + O-phospho-L-threonyl-[protein] Interacts with yki and ex (PubMed:27462444). Interacts with drk (PubMed:22615583). Likely to be a member of an axonal guidance receptor complex that includes SH3PX1, dock and Dscam (PubMed:11773052). Interacts (via N-terminus) with dock (PubMed:23562806, PubMed:11773052). Interacts with SH3PX1 (via SH3 domain) (PubMed:11773052). In nurse cells localizes to cytoophidium, a subcellular filamentary structure where CTP synthase is compartmentalized (PubMed:25223282). In third instar photoreceptor R-cells, expressed in the cytoplasm and cytoplasmic puncta (PubMed:22615583). In spermatocytes displays localization to peripheral clathrin-positive structures and localization to some secretory clathrin (PubMed:23562806). Detected in ovaries (at protein level) (PubMed:25223282). In adults, relatively higher expression in the head compared to the body (PubMed:11997505). In stage 13 embryos at the beginning of dorsal closure, enriched in the leading edge of the epidermis (at protein level). The SAM, Protein kinase and SH3 domains are required for sperm formation. The SAM and SH3 domains are required for localization to clathrin-coated vesicles in spermatocytes. Phosphorylated (PubMed:22615583). Autophosphorylated (PubMed:11773052). No visible developmental defects but males and females display reduced fertility (PubMed:27462444, PubMed:22615583, PubMed:23562806). Males are sterile due to disruption of spermatid coiling (PubMed:27462444, PubMed:22615583, PubMed:23562806). Spermatids individualization complexes are displaced from the outer region of the testis coil to the inner region and display increased apoptosis (PubMed:22615583). During oogenesis, defective assembly and disassembly of cytoophidium in nurse cells result in a range of phenotypes resulting from reduced CTP production (PubMed:25223282). These include reduced egg laying, disruptions in the plasma membrane between adjacent nurse cells that result in the nurse cells fusing, and reduced nurse cell nuclei diameter most likely as a result of defective endoreplication (PubMed:25223282). Cytoophidium are observed in the germanium at an earlier developmental stage and persist inappropriately into late-stage egg chambers (PubMed:25223282). The number of cytoophidium in the cytoplasm of nurse cells is increased and their length is reduced (PubMed:25223282). Enhances the small eye phenotype in hid mutants (PubMed:22615583). Developing embryos display a very low frequently of dorsal defects (PubMed:18816840). Simultaneous knockdown of Ack and Ack-like results in many embryos failing to properly secrete the cuticle likely due to the loss of zip expression (PubMed:18816840). Mutants also display defects in the dorsal surface including holes in the cuticle and germband retraction failure (PubMed:18816840). Belongs to the protein kinase superfamily. Tyr protein kinase family.