SRBC/cavin-3 is a caveolin adapter protein that regulates caveolae function.
Caveolae are a major membrane domain common to most cells. One of the defining features of this domain is the protein caveolin. The exact function of caveolin, however, is not clear. One possible function is to attract adapter molecules to caveolae in a manner similar to how clathrin attracts molecules to coated pits. Here, we characterize a candidate adapter molecule called SRBC. SRBC binds PKCdelta and is a member of the STICK (substrates that interact with C-kinase) superfamily of PKC-binding proteins. We also show it co-immunoprecipitates with caveolin-1. A leucine zipper in SRBC is essential for both co-precipitation with caveolin and localization to caveolae. SRBC remains associated with caveolin when caveolae bud to form vesicles (cavicles) that travel on microtubules to different regions of the cell. In the absence of SRBC, intracellular cavicle traffic is markedly impaired. We conclude that SRBC (sdr-related gene product that binds to c-kinase) and two other family members [PTRF (Pol I and transcription release factor) and SDPR] function as caveolin adapter molecules that regulate caveolae function.
McMahon
Kerrie-Ann
KA
Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9039, USA.
Zajicek
Hubert
H
Li
Wei-Ping
WP
Peyton
Michael J
MJ
Minna
John D
JD
Hernandez
V James
VJ
Luby-Phelps
Katherine
K
Anderson
Richard G W
RG
D000818:Animals; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D021941:Caveolae / Q000378:metabolism*; D022461:Caveolins / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D022162:Cytoplasmic Vesicles / Q000378:metabolism / Q000648:ultrastructure; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism; D036681:Fluorescence Recovery After Photobleaching; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D018345:Mice, Knockout; D016297:Mutagenesis, Site-Directed; D028044:Phosphate-Binding Proteins; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D011493:Protein Kinase C / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D014018:Tissue Distribution
C497835:CAVIN1 protein, human; C112303:CAVIN2 protein, human; C505360:CAVIN3 protein, human; D002352:Carrier Proteins; D022461:Caveolins; D047908:Intracellular Signaling Peptides and Proteins; D028044:Phosphate-Binding Proteins; D020033:Protein Isoforms; D016601:RNA-Binding Proteins; D011993:Recombinant Fusion Proteins; D011493:Protein Kinase C