Aggregates of large mitochondria (red) form when Rab32 (green) cannot bind GTP (top).

The large family of Rab GTPases has various functions, including the assembly of proteins required for endocytosis and membrane trafficking. Now, a new function for a Rab is emerging. On page 659, Alto et al. describe a Rab that affects mitochondrial fission. This GTPase, Rab32, also has an unusual binding partner, the cAMP-dependent kinase PKA.

The authors originally sought to identify novel AKAPs, proteins that anchor PKA to subcellular domains. They found Rab32, the first Ras family member GTPase shown to interact directly with PKA. Although a functional connection between the two has yet to be shown, association of the enzymes may facilitate localization of signal transduction pathways. The group is currently addressing this possibility by looking for other proteins that may interact with the complex.

After confirming that Rab32 was...

The Rockefeller University Press
2002
The Rockefeller University Press
2002
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