Essential protein for male fertility. Component of the SCF(ASK-cullin-F-box) E3 ubiquitin ligase complex SCF(FBL17), which mediates the ubiquitination and subsequent proteasomal degradation of target proteins. Enables the switch in cell cycle control leading to male germ cell lineage formation from microspores after meiosis. Targets CDKA-1 inhibitors the degradation specifically in male germ cells (e.g. KRP6 and KRP7) and thus enables CDKA-1 activation and germ cell S-phase progression. Promotes twin sperm cell production and double fertilization. Protein modification; protein ubiquitination. Part of a SCF (ASK-cullin-F-box) protein ligase complex. Interacts with SKP1A/ASK1, KRP4, KRP6 AND KRP7. Confined to the male germ cell nucleus of early to mid bicellular pollen. Expressed in developing pollen. Expressed transiently in the male germ line after asymmetric division. Present in maturing pollen with highest levels in bicellular pollen. The F-box is necessary for the interaction with ASK proteins. Stabilization of KRP6 and inhibition of germ cell cycle progression leading to male sterility.