The endosome-associated protein Hrs is hexameric and controls cargo sorting as a "master molecule".
The structure of the endosomal-associated protein, Hrs, has been determined with cryo-electron microscopy. Hrs interacts with a number of proteins, including SNAP-25 and STAM1, forming a complex that binds ubiquitin moieties. Analytical ultracentrifugation studies revealed that Hrs exists as a hexamer. The symmetry and the structure of the hexameric form of Hrs were determined with the single-particle reconstruction method. Hrs comprises three antiparallel dimers with a central core and distinct caps on either end. Crystal structures of VHS and FYVE domains fit into the Hrs end caps in the EM density map. Thus, the location of domains that interact with the endosomal membrane, the VHS, FYVE, and C-terminal domains, facilitates the anchorage of Hrs to the membrane, initiating the functional processes of Hrs on the endosome. Based on our model, the Hrs hexamer interacts with the membrane and acts as a "master molecule" that presents multiple sites for protein binding.
Pullan
Lee
L
Department of Biochemistry and Molecular Biology, The University of Texas-Houston Medical School, 6431 Fannin, Houston, Texas 77030, USA.
Mullapudi
Srinivas
S
Huang
Zhong
Z
Baldwin
Philip R
PR
Chin
Christopher
C
Sun
Wei
W
Tsujimoto
Susan
S
Kolodziej
Steven J
SJ
Stoops
James K
JK
Lee
J Ching
JC
Waxham
M Neal
MN
Bean
Andrew J
AJ
Penczek
Pawel A
PA
D048868:Adaptor Proteins, Signal Transducing / Q000737:chemistry; D000595:Amino Acid Sequence; D000818:Animals; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D002850:Chromatography, Gel; D020285:Cryoelectron Microscopy / Q000379:methods*; D018360:Crystallography, X-Ray; D019281:Dimerization; D004305:Dose-Response Relationship, Drug; D056827:Endosomal Sorting Complexes Required for Transport; D011992:Endosomes / Q000737:chemistry* / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007313:Insecta; D051379:Mice; D008854:Microscopy, Electron; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010750:Phosphoproteins / Q000737:chemistry* / Q000378:metabolism*; D011485:Protein Binding; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D021381:Protein Transport; D011506:Proteins / Q000737:chemistry; D050825:Synaptosomal-Associated Protein 25 / Q000737:chemistry; D014461:Ultracentrifugation
D048868:Adaptor Proteins, Signal Transducing; D056827:Endosomal Sorting Complexes Required for Transport; D010750:Phosphoproteins; D011506:Proteins; C494208:SNAP25 protein, human; C109775:STAM protein, human; D050825:Synaptosomal-Associated Protein 25; C096164:hepatocyte growth factor-regulated tyrosine kinase substrate