Profilin: at the crossroads of signal transduction and the actin cytoskeleton.
Despite its small size, profilin is an amazingly diverse and sophisticated protein whose precise role in cells continues to elude the understanding of researchers 15 years after its discovery. Its ubiquity, abundance and necessity for life in more evolved organisms certainly speaks for its extreme importance in cell function. So far, three ligands for profilin have been well-characterized in vitro: actin monomers, membrane polyphosphoinositides and poly-L-proline. In the years following its discovery, profilin's role in vivo progressed from that of a simple actin-binding protein which inhibits actin polymerization, to one which, as an important regulator of the cytoskeleton, can even promote actin polymerization under the appropriate circumstances. In addition, interactions with components of the phosphatidylinositol cycle and the RAS pathway in yeast implicate profilin as an important link through which the actin cytoskeleton is able to communicate with major signaling pathways.
Sohn
R H
RH
Bernard Laboratory for Fundamental Research in Preventive Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287.
Goldschmidt-Clermont
P J
PJ
D000199:Actins / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D003285:Contractile Proteins; D003599:Cytoskeleton / Q000378:metabolism; D019204:GTP-Binding Proteins / Q000378:metabolism; D006801:Humans; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D008840:Microfilament Proteins / Q000502:physiology*; D008969:Molecular Sequence Data; D018129:Phosphatidylinositol Phosphates / Q000378:metabolism; D051304:Profilins; D020794:Receptor Protein-Tyrosine Kinases / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology
D000199:Actins; D001426:Bacterial Proteins; D003285:Contractile Proteins; D008565:Membrane Proteins; D008840:Microfilament Proteins; C495738:PFN1 protein, human; D018129:Phosphatidylinositol Phosphates; D051304:Profilins; C072980:actA protein, Listeria monocytogenes; D020794:Receptor Protein-Tyrosine Kinases; D019204:GTP-Binding Proteins