ATP + L-seryl-[protein] = ADP + H(+) + O-phospho-L-seryl-[protein] ATP + L-threonyl-[protein] = ADP + H(+) + O-phospho-L-threonyl-[protein] Expression remains constant as development proceeds. Subtle morphological defects such as an aberrant stalk structure; due to the redundancy between ifkA and ifkB functions. Cells lacking ifkA and ifkB display severe morphological and patterning defects. Mutant cells aggregate in streams that give tightly clumped mounds. Fingers form from the mounds but remain attached to one another, especially at their bases. The fingers culminate to give fused and entangled structures lacking proper stalk but containing some spores. The morphological defects are consistent with an enhanced cell-cell and cell-substrate adhesiveness of the developing double null cells, which may result in inappropriate cell contacts and altered cell motility and sorting properties. Belongs to the protein kinase superfamily. Ser/Thr protein kinase family. GCN2 subfamily.