Inner nuclear membrane protein (PubMed:16439308). Acts as a negative regulator of the BMP (Dpp) signaling cascade during crossvein development in pupal wings and possibly during synaptic transmission at the neuromuscular junction (NMJ) (PubMed:18723885, PubMed:20036230). Appears to be required for pupal development and consequently transition to the adult stage (PubMed:18723885, PubMed:20036230). During pupal development, plays essential and redundant functions with the other LEM domain proteins; bocks and Ote (PubMed:24700158). Interacts with Lam and LamC (PubMed:16439308). Interacts with Mad (PubMed:20036230). Interacts (via N-terminus) with baf (PubMed:20036230). During anaphase and metaphase, detected in the nuclear envelope and spindle poles. High levels of expression in eggs and first instar larvae (at protein level) (PubMed:16439308). Levels decline between the second and third instar stages, and then increase during the pupal to adult stages (at protein level) (PubMed:16439308). Expressed in the pupal and larval wing (PubMed:20036230). In pupal wings, expression appears to be enhanced in the presumptive longitudinal veins (PubMed:20036230). Loss of maternal and zygotic activity results in a reduction in survival at each developmental stage, with mutants rarely surviving to the adult stage (PubMed:18723885). Adult escapers display held out wings and exhibit wing patterning defects with thickened longitudinal veins, a varied number of anterior crossveins, branched posterior crossvein and folded wing blades (PubMed:18723885). In adults, climbing is impaired and their climbing ability further decreases with age (PubMed:18723885). Males are sterile and females display reduced fecundity (PubMed:18723885). No significant decrease in adult survival, however double mutants with either Ote or bocks do not survive to the adult stage (PubMed:24700158). No effect on nuclear envelope formation (PubMed:18723885). Larval brain size and imaginal disks are normal in double mutants with either Ote or bocks (PubMed:24700158). Truncated N-terminus.