Rab32 is an A-kinase anchoring protein and participates in mitochondrial dynamics

Neal M. Alto, Jacquelyn Soderling, John D. Scott

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163 Scopus citations

Abstract

A-kinase anchoring proteins (AKAPs) tether the cAMP-dependent protein kinase (PKA) and other signaling enzymes to distinct subcellular organelles. Using the yeast two-hybrid approach, we demonstrate that Rab32, a member of the Ras superfamily of small molecular weight G-proteins, interacts directly with the type II regulatory subunit of PKA. Cellular and biochemical studies confirm that Rab32 functions as an AKAP inside cells. Anchoring determinants for PKA have been mapped to sites within the conserved α5 helix that is common to all Rab family members. Subcellular fractionation and immunofluorescent approaches indicate that Rab32 and a proportion of the cellular PKA pool are associated with mitochondria. Transient transfection of a GTP binding-deficient mutant of Rab32 promotes aberrant accumulation of mitochondria at the microtubule organizing center. Further analysis of this mutant indicates that disruption of the microtubule cyto-skeleton results in aberrantly elongated mitochondria. This implicates Rab32 as a participant in synchronization of mitochondrial fission. Thus, Rab32 is a dual function protein that participates in both mitochondrial anchoring of PKA and mitochondrial dynamics.

Original languageEnglish (US)
Pages (from-to)659-668
Number of pages10
JournalJournal of Cell Biology
Volume158
Issue number4
DOIs
StatePublished - Aug 19 2002

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Keywords

  • Anchoring protein
  • Mitochondria
  • Protein kinase
  • Rab protein
  • cAMP

ASJC Scopus subject areas

  • Cell Biology

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