Abl regulates hemocyte homeostasis independently of PTP61F. (A) Confocal images of DAPI-stained peripheral (circulating and sessile) hemocytes from late-third instar larvae of the following genotypes: HmlΔ-GAL4/+, UAS-Abl/+; HmlΔ-GAL4/+ (HmlΔ > Abl), HmlΔ-GAL4/UAS-PTP61F (HmlΔ > PTP61F), UAS-Abl/+; HmlΔ-GAL4/UAS-PTP61F (HmlΔ > Abl, PTP61F), WT, Abl¹/Abl⁴, PTP61F^C05292/Df(3L)BSC289 (PTP61F^P/PTP61F^Df), and PTP61F^C05292,Abl¹/Df(3L)BSC289,Abl⁴ (PTP61F^P, Abl¹/PTP61F^Df,Abl⁴). (B) Number of peripheral hemocytes per larva. n = 12 larvae. (C) Confocal images of peripheral hemocytes from late-third instar larvae in the indicated genotypes shown in B, stained with anti-L1 (green) and DAPI (blue). Arrowheads indicate L1⁺ lamellocytes. (D) Percentage of L1⁺ lamellocytes among all peripheral hemocytes (total DAPI count). (E) Confocal images of peripheral hemocytes from late-third instar larvae in the indicated genotypes shown in Fig. 8 F, stained with anti-L1 (green) and DAPI (blue). Arrowheads indicate L1⁺ lamellocytes. (F) Percentage of L1⁺ lamellocytes among all peripheral hemocytes. (G) Model for the opposite regulation of CME-mediated Notch signaling activation and blood cell homeostasis by Abl-mediated Abi phosphorylation and PTP61F-mediated dephosphorylation. Data represent the mean ± SEM. Comparisons are with HmlΔ-GAL4/+ unless otherwise indicated. Statistical analyses were performed using a one-way ANOVA with the Tukey–Kramer post hoc test (*P < 0.05; **P < 0.01; ***P < 0.001; ns, not significant). Scale bars: 20 μm.