CVAK104 is a novel regulator of clathrin-mediated SNARE sorting.
Clathrin-coated vesicles (CCVs) mediate transport between the plasma membrane, endosomes and the trans Golgi network. Using comparative proteomics, we have identified coated-vesicle-associated kinase of 104 kDa (CVAK104) as a candidate accessory protein for CCV-mediated trafficking. Here, we demonstrate that the protein colocalizes with clathrin and adaptor protein-1 (AP-1), and that it is associated with a transferrin-positive endosomal compartment. Consistent with these observations, clathrin as well as the cargo adaptors AP-1 and epsinR can be coimmunoprecipitated with CVAK104. Small interfering RNA (siRNA) knockdown of CVAK104 in HeLa cells results in selective loss of the SNARE proteins syntaxin 8 and vti1b from CCVs. Morpholino-mediated knockdown of CVAK104 in Xenopus tropicalis causes severe developmental defects, including a bent body axis and ventral oedema. Thus, CVAK104 is an evolutionarily conserved protein involved in SNARE sorting that is essential for normal embryonic development.
Borner
Georg H H
GH
CIMR, University of Cambridge, Cambridge CB2 0XY, UK.
Rana
Amer A
AA
Forster
Rebecca
R
Harbour
Michael
M
Smith
James C
JC
Robinson
Margaret S
MS
D033942:Adaptor Proteins, Vesicular Transport / Q000378:metabolism; D000818:Animals; D001692:Biological Transport; D002462:Cell Membrane / Q000378:metabolism; D002966:Clathrin / Q000378:metabolism*; D011992:Endosomes / Q000378:metabolism; D019143:Evolution, Molecular; D006367:HeLa Cells; D006801:Humans; D051379:Mice; D017346:Protein Serine-Threonine Kinases / Q000502:physiology*; D050765:Qa-SNARE Proteins / Q000378:metabolism; D034741:RNA, Small Interfering / Q000378:metabolism; D050600:SNARE Proteins / Q000378:metabolism*; D014981:Xenopus / Q000378:metabolism
D033942:Adaptor Proteins, Vesicular Transport; C475910:CLINT1 protein, human; D002966:Clathrin; D050765:Qa-SNARE Proteins; D034741:RNA, Small Interfering; D050600:SNARE Proteins; D017346:Protein Serine-Threonine Kinases; C501863:SCYL2 protein, human