FIG. 6.

Model of interaction between AMPK α1 and NDPK-A. The phosphorylation status of residue S122 on NDPK-A determines whether NDPK-A channels ATP derived from GTP plus ADP to AMPK α1 as the substrate in the phosphorylation of downstream AMPK targets, for example, ACC1. Mutation of residue E124K on NDPK-A eliminates the specific interaction of NDPK-A with AMPK α1 (not shown). Serine 144 was also identified as an AMPK α1 target, but experiments revealed that its phosphorylation status has no bearing on substrate channeling or ACC1 phosphorylation. Peptides (Pep) 1 to 4 refer to surface regions of NDPK-A.