NH2-Terminal Targeting Motifs Direct Dual Specificity A-Kinase–anchoring Protein 1 (D-AKAP1) to Either Mitochondria or Endoplasmic Reticulum

• DOI: 10.1083/jcb.145.5.951
• Publication Date: 2002-07-26T16:45:41Z
• Authors: Lily Jun-shen Huang; Lin Wang; Yuliang Ma; Kyle Durick; Guy Perkins; Thomas J. Deerinck; Mark H. Ellisman; Susan S. Taylor
• Keywords: splice

Subcellular localization directed by specific targeting motifs is an emerging theme for regulating signal transduction pathways. For cAMP-dependent protein kinase (PKA), this achieved primarily its association with A-kinase–anchoring proteins (AKAPs). Dual specificity AKAP1, (D-AKAP1) binds to both type I and II regulatory subunits has two NH2-terminal (N0 N1) COOH-terminal (C1 C2) splice variants (Huang et al., 1997. J. Biol. Chem. 272:8057). Here we report that the of D-AKAP1 are expressed in a tissue-specific manner serving as switches localize at different sites. Northern blots showed N1 liver, while C1 predominant testis. The C2 shows general expression pattern. Microinjecting constructs D-AKAP1(N0) epitope-tagged either NH2 or COOH terminus their mitochondria based on immunocytochemistry. Deletion N0(1-30) abolished mitochondrial N0(1-30)-GFP localized mitochondria. Residues 1–30 N0 therefore necessary sufficient targeting. Addition 33 residues targets ER 1–63 fused GFP 14–33 especially important ER; however, 1–33 alone gave diffuse distribution. N1(14-33) thus serves functions: (a) it suppresses mitochondrial-targeting motif located within (b) exposes ER-targeting least partially contained motif. This represents first example differentially targeted AKAP adds additional level complexity PKA signaling network.