KR456/457 of Gwl mediates importin binding. (A) Schematic representation of various Gwl constructs. (B) Oocytes were injected with mRNAs encoding Flag-tagged full length (FL), NT, or CT-Gwl and incubated overnight. Oocytes were then treated with progesterone and collected at MI. Lysates from the MI oocytes were precipitated with anti-Flag antibody beads, and the precipitates were immunoblotted for Flag, importin β, and importin α. Uninjected oocyte lysates treated with Flag antibody beads served as a control (marked as C). (C) The N1 Fragment of Gwl Binds Hsp90 but not importins. Oocytes were injected with mRNA encoding the Flag-tagged full-length and N1 fragment of Gwl and analyzed by immunoblotting using antibodies against Flag, importin β, importin α, and Hsp90. (D) KR456/457 is essential for Gwl binding to importins. Oocytes at G2 phase were injected with mRNA encoding WT or KR456/457AA Flag-Gwl and incubated overnight. Some oocytes were then treated with progesterone and collected at MI. Uninjected G2 oocytes were treated identically as a control (marked as C, G2). Lysates from the G2 and MI oocytes were precipitated with anti-Flag antibody beads, and the precipitates were immunoblotted using Flag, importin β, and importin α antibodies.