Phosducin-like proteins in Dictyostelium discoideum: implications for the phosducin family of proteins


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Blaauw M., Knol J., Kortholt A., Roelofs J., Ruchira R., Postma M., ...More

EMBO JOURNAL, vol.22, no.19, pp.5047-5057, 2003 (Peer-Reviewed Journal) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 22 Issue: 19
  • Publication Date: 2003
  • Doi Number: 10.1093/emboj/cdg508
  • Journal Name: EMBO JOURNAL
  • Journal Indexes: Science Citation Index Expanded, Scopus
  • Page Numbers: pp.5047-5057
  • Keywords: chaperone, Dictyostelium, G protein, signal transduction, phosducin, G-BETA-GAMMA, HETEROTRIMERIC G-PROTEINS, SUBUNIT FUNCTION, REGULATOR, COMPLEX, CHEMOTAXIS, TRANSDUCIN, CELLS, PHLP, GRADIENTS

Abstract

Retinal phosducin is known to sequester transducin Gbetagamma, thereby modulating transducin activity. Phos ducin is a member of a family of phosducin-like proteins (PhLP) found in eukaryotes. Phylogeny of 33 phosducin-like proteins from metazoa, plants and lower eukaryotes identified three distinct groups named phosducin-I-III. We discovered three phlp genes in Dictyostelium, each encoding a phosducin-like protein of a different group. Disruption of the phlp1 gene strongly impaired G-protein signalling, apparently due to mislocalization of Gbetagamma in phlp1-null cells. GFP-Gbeta and GFP-Ggamma are membrane associated in wild-type cells, but cytosolic in phlp1-null cells. Phlp2 disruption is lethal due to a synchronous collapse of the cells after 16-17 cell divisions. Phlp3 disruptants show no abnormal phenotype. These results establish a role for phosducin-like proteins in facilitating folding, localization or function of proteins, in addition to modulating G-protein signalling.