Multiple ubiquitin conjugates are present in rat brain synaptic membranes and postsynaptic densities.
The pattern of ubiquitin-protein conjugates present in a range of adult rat forebrain subcellular fractions has been investigated by immunoblotting with a monoclonal antibody specific for ubiquitin and its conjugates. Each fraction contains a complex and characteristic pattern of ubiquitin conjugates. Many integral synaptic membrane proteins are ubiquitinated, including a subset of high M(r) (> 120 kD) concanavalin A-binding glycoproteins. Postsynaptic densities are also enriched in ubiquitin conjugates, the profile being distinct from that of synaptic membranes. These results suggest that many plasma membrane and synaptic proteins are ubiquitinated.
Department of Biochemistry, Royal Holloway and Bedford New College, University of London, Egham, Surrey, UK.
A P
AP
Chapman
S J
SJ
Smith
C C
CC
Rider
P W
PW
Beesley
D000818:Animals; D000911:Antibodies, Monoclonal; D015153:Blotting, Western; D003208:Concanavalin A; D004591:Electrophoresis, Polyacrylamide Gel; D004797:Enzyme-Linked Immunosorbent Assay; D008970:Molecular Weight; D009419:Nerve Tissue Proteins / Q000032:analysis* / Q000302:isolation & purification; D016548:Prosencephalon / Q000737:chemistry*; D011485:Protein Binding; D051381:Rats; D013347:Subcellular Fractions / Q000737:chemistry; D013569:Synapses / Q000737:chemistry*; D013570:Synaptic Membranes / Q000737:chemistry*; D014452:Ubiquitins / Q000032:analysis* / Q000302:isolation & purification
D000911:Antibodies, Monoclonal; D009419:Nerve Tissue Proteins; D014452:Ubiquitins; D003208:Concanavalin A