Phosphorylates eIF2-alpha, from 1 to 7 hours after the onset of development or during the preaggregation state, resulting in a shift from polysomes to free ribosomes for bulk mRNA. ATP + L-seryl-[protein] = ADP + H(+) + O-phospho-L-seryl-[protein] ATP + L-threonyl-[protein] = ADP + H(+) + O-phospho-L-threonyl-[protein] Expression dramatically drops soon after the onset of development and remains at a low level for the remainder of development. IfkA null cells have defects such as an earlier aggregation, a formation of larger than normal mounds and ultimately a formation of fruiting bodies that are also larger than normal. The early aggregation phenotype reflects an apparent, earlier than normal establishment of the cAMP pulsing system. 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. Belongs to the protein kinase superfamily. Ser/Thr protein kinase family.