Microtubules and actin microfilaments regulate lipid raft/caveolae localization of adenylyl cyclase signaling components

J Biol Chem. 2006 Sep 8;281(36):26391-9. doi: 10.1074/jbc.M602577200. Epub 2006 Jul 3.


Microtubules and actin filaments regulate plasma membrane topography, but their role in compartmentation of caveolae-resident signaling components, in particular G protein-coupled receptors (GPCR) and their stimulation of cAMP production, has not been defined. We hypothesized that the microtubular and actin cytoskeletons influence the expression and function of lipid rafts/caveolae, thereby regulating the distribution of GPCR signaling components that promote cAMP formation. Depolymerization of microtubules with colchicine (Colch) or actin microfilaments with cytochalasin D (CD) dramatically reduced the amount of caveolin-3 in buoyant (sucrose density) fractions of adult rat cardiac myocytes. Colch or CD treatment led to the exclusion of caveolin-1, caveolin-2, beta1-adrenergic receptors (beta1-AR), beta2-AR, Galpha(s), and adenylyl cyclase (AC)5/6 from buoyant fractions, decreasing AC5/6 and tyrosine-phosphorylated caveolin-1 in caveolin-1 immunoprecipitates but in parallel increased isoproterenol (beta-AR agonist)-stimulated cAMP production. Incubation with Colch decreased co-localization (by immunofluorescence microscopy) of caveolin-3 and alpha-tubulin; both Colch and CD decreased co-localization of caveolin-3 and filamin (an F-actin cross-linking protein), decreased phosphorylation of caveolin-1, Src, and p38 MAPK, and reduced the number of caveolae/mum of sarcolemma (determined by electron microscopy). Treatment of S49 T-lymphoma cells (which possess lipid rafts but lack caveolae) with CD or Colch redistributed a lipid raft marker (linker for activation of T cells (LAT)) and Galpha(s) from lipid raft domains. We conclude that microtubules and actin filaments restrict cAMP formation by regulating the localization and interaction of GPCR-G(s)-AC in lipid rafts/caveolae.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Actin Cytoskeleton / metabolism*
  • Actins / metabolism*
  • Adenylyl Cyclases / genetics
  • Adenylyl Cyclases / metabolism*
  • Adrenergic beta-Agonists / metabolism
  • Animals
  • Caveolae / metabolism*
  • Caveolins / genetics
  • Caveolins / metabolism
  • Cell Fractionation
  • Cells, Cultured
  • Colchicine / metabolism
  • Contractile Proteins / metabolism
  • Cyclic AMP / metabolism
  • Cytochalasin D / metabolism
  • Cytoskeleton / metabolism
  • Filamins
  • Isoproterenol / metabolism
  • Male
  • Membrane Microdomains / metabolism*
  • Mice
  • Mice, Knockout
  • Microfilament Proteins / metabolism
  • Microtubules / metabolism*
  • Models, Biological
  • Myocytes, Cardiac / metabolism
  • Myocytes, Cardiac / ultrastructure
  • Nucleic Acid Synthesis Inhibitors / metabolism
  • Protein Isoforms / genetics
  • Protein Isoforms / metabolism
  • Rats
  • Rats, Sprague-Dawley
  • Receptors, Adrenergic, beta / metabolism
  • Receptors, G-Protein-Coupled / metabolism
  • Sarcolemma / metabolism
  • Sarcolemma / ultrastructure
  • Signal Transduction / physiology*
  • Tubulin Modulators / metabolism


  • Actins
  • Adrenergic beta-Agonists
  • Caveolins
  • Contractile Proteins
  • Filamins
  • Microfilament Proteins
  • Nucleic Acid Synthesis Inhibitors
  • Protein Isoforms
  • Receptors, Adrenergic, beta
  • Receptors, G-Protein-Coupled
  • Tubulin Modulators
  • Cytochalasin D
  • Cyclic AMP
  • Adenylyl Cyclases
  • Isoproterenol
  • Colchicine