Membrane Localization of Cyclic Nucleotide Phosphodiesterase 3 (PDE3)

摘要: Subcellular localization of cyclic nucleotide phosphodiesterases (PDEs) may be important in compartmentalization cAMP/cGMP signaling responses. In 3T3-L1 adipocytes, mouse (M) PDE3B was associated with the endoplasmic reticulum (ER) as indicated by its immunofluorescent colocalization ER protein BiP and subcellular fractionation studies. transfected NIH 3006 or COS-7 cells, recombinant wild-type PDE3A isoforms were both found almost exclusively ER. The N-terminal portion PDE3 can arbitrarily divided into region 1 (aa 1-300), which contains a large hydrophobic domain six predicted transmembrane helices, followed 2 301-500) containing smaller (of approximately 50 aa). To investigate role regions membrane association, we examined series catalytically active, Flag-tagged N-terminal-truncated human (H) MPDE3B recombinants, well fragments from synthesized enhanced green fluorescent (EGFP) fusion proteins cells. mutant HPDE3A, lacking first 189 amino acids (aa) therefore four helices (H3A-Delta189), virtually identical to that wild type. M3B-Delta302 (lacking 1) H3A-Delta397 part 2) retained, different degrees, ability associate membranes, albeit less efficiently than H3A-Delta189. Proteins lacked 2, H3A-Delta510 M3B-Delta604, did not membranes. Consistent these findings, EGFP-MPDE3B colocalized ER, whereas EGFP diffusely distributed. Thus, some plus second are for efficient association/targeting PDE3.