Engrailed homeoprotein secretion is a regulated process.
Chicken Engrailed 2 homeoprotein is transported between cells in culture. This intercellular transfer is based on unconventional secretion and internalisation mechanisms: Engrailed 2 has access to vesicles but lacks a signal sequence for secretion and is internalised by a non-endocytic process. We show that phosphorylation of a serine-rich domain within Engrailed 2 by the protein kinase CK2 specifically inhibits Engrailed 2 secretion. The availability of the serine-rich domain to CK2 is highly increased when it is displaced from its normal position to the C terminus of Engrailed 2, leading to a constitutive blockage of Engrailed 2 intercellular transfer. This indicates that intercellular transfer of Engrailed 2 is a highly regulated process.
Biologie cellulaire des homéoprotéines, CNRS UMR8542 Ecole Normale Supérieure 46 rue d'Ulm F-75005 Paris, France.
Alexis
A
Maizel
Michel
M
Tassetto
Odile
O
Filhol
Claude
C
Cochet
Alain
A
Prochiantz
Alain
A
Joliot
D000818:Animals; D001692:Biological Transport / Q000502:physiology*; D019556:COS Cells; D047390:Casein Kinase II; D002478:Cells, Cultured; D002645:Chickens; D004268:DNA-Binding Proteins / Q000378:metabolism; D005801:Genes, Homeobox; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism*; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D010446:Peptide Fragments / Q000378:metabolism; D010750:Phosphoproteins / Q000378:metabolism; D010766:Phosphorylation; D020033:Protein Isoforms; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D051381:Rats; D012694:Serine / Q000378:metabolism; D000099266:Engrailed 2 Protein
D047390:Casein Kinase II; D004268:DNA-Binding Proteins; D018398:Homeodomain Proteins; D009419:Nerve Tissue Proteins; D010446:Peptide Fragments; D010750:Phosphoproteins; D020033:Protein Isoforms; D017346:Protein Serine-Threonine Kinases; D012694:Serine; D000099266:Engrailed 2 Protein