TY - JOUR
T1 - Autoinhibition of the ligand-binding site of GGA1/3 VHS domains by an internal acidic cluster-dileucine motif
AU - Doray, Balraj
AU - Bruns, Kerry
AU - Ghosh, Pradipta
AU - Kornfeld, Stuart A.
PY - 2002/6/11
Y1 - 2002/6/11
N2 - The GGAs (Golgi-localizing, γ-adaptin ear homology domain, ARF-binding proteins) are a family of proteins implicated in protein trafficking from the Golgi to endosomes/lysosomes. These proteins have modular structures with an N-terminal VHS (VPS-27, Hrs, and STAM) domain followed by a GAT (GGA and TOM1) domain, a connecting hinge segment, and a C-terminal GAE (γ-adaptin ear) domain. Isolated VHS domains have been shown to bind specifically to acidic cluster (AC)-dileucine motifs present in the cytoplasmic tails of the mannose 6-phosphate receptors. Here we report that full-length cytoplasmic GGA1 and GGA3 but not GGA2 bind the cation-independent mannose 6-phosphate receptor very poorly because of autoinhibition. This inhibition is caused by the binding of an AC-LL sequence present in the hinge segment to the ligand-binding site in the VHS domain. The inhibition depends on the phosphorylation of a serine located three residues upstream of the AC-LL motif. The serine is phosphorylated by casein kinase 2 in in vitro assays. Substitution of the GGA1 inhibitory sequence into the analogous location in GGA2, which lacks the AC-LL motif, results in autoinhibition of the latter protein. These data indicate that the activity of GGA1 and GGA3 is regulated by cycles of phosphorylation/dephosphorylation.
AB - The GGAs (Golgi-localizing, γ-adaptin ear homology domain, ARF-binding proteins) are a family of proteins implicated in protein trafficking from the Golgi to endosomes/lysosomes. These proteins have modular structures with an N-terminal VHS (VPS-27, Hrs, and STAM) domain followed by a GAT (GGA and TOM1) domain, a connecting hinge segment, and a C-terminal GAE (γ-adaptin ear) domain. Isolated VHS domains have been shown to bind specifically to acidic cluster (AC)-dileucine motifs present in the cytoplasmic tails of the mannose 6-phosphate receptors. Here we report that full-length cytoplasmic GGA1 and GGA3 but not GGA2 bind the cation-independent mannose 6-phosphate receptor very poorly because of autoinhibition. This inhibition is caused by the binding of an AC-LL sequence present in the hinge segment to the ligand-binding site in the VHS domain. The inhibition depends on the phosphorylation of a serine located three residues upstream of the AC-LL motif. The serine is phosphorylated by casein kinase 2 in in vitro assays. Substitution of the GGA1 inhibitory sequence into the analogous location in GGA2, which lacks the AC-LL motif, results in autoinhibition of the latter protein. These data indicate that the activity of GGA1 and GGA3 is regulated by cycles of phosphorylation/dephosphorylation.
UR - http://www.scopus.com/inward/record.url?scp=0037062410&partnerID=8YFLogxK
U2 - 10.1073/pnas.082235699
DO - 10.1073/pnas.082235699
M3 - Article
C2 - 12060753
AN - SCOPUS:0037062410
SN - 0027-8424
VL - 99
SP - 8072
EP - 8077
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
IS - 12
ER -