FRET reveals novel protein-receptor interaction of bone morphogenetic proteins receptors and adaptor protein 2 at the cell surface.
Bone morphogenetic proteins (BMPs) are involved with a wide range of processes including apoptosis, differentiation, and proliferation. Several different pathways such as Smad, p38, and PI3/Akt are activated by BMPs. Signaling is transduced by BMP receptors (BMPRs) of type I and type II that are serine/threonine kinase receptors. BMPRs shuttle between membrane domains such as caveolae enriched with caveolin-1 beta-isoform and caveolae of the caveolin-1 alpha/beta-isoforms. It is hypothesized that there are other membrane domains to which the receptors localize. We used immunoprecipitation, Western blots, image cross-correlation spectroscopy, and fluorescence resonance energy transfer to investigate the interaction of BMPRs with proteins in clathrin-coated pits (CCPs). Our data indicate that these domains are associated with at least two of the BMPRs: BRIa and BRII. For the first time, to our knowledge, we showed what we believe are specific interactions between BRIa and BRII with a key component of CCPs, adaptor protein 2. Further, disruption of CCPs resulted in increased BRIa aggregation at the cell surface and activation of the BMP pathway even in the absence of BMP2. Therefore, CCPs seem to function as a negative regulatory membrane domain for BMP pathway activation.
Bragdon
Beth
B
Department of Biological Sciences, University of Delaware, Newark, Delaware, USA.
Thinakaran
Shayamala
S
Bonor
Jeremy
J
Underhill
T Michael
TM
Petersen
Nils O
NO
Nohe
Anja
A
D033962:Adaptor Protein Complex 2 / Q000378:metabolism*; D000818:Animals; D055396:Bone Morphogenetic Protein 2 / Q000378:metabolism; D052005:Bone Morphogenetic Protein Receptors, Type I / Q000378:metabolism*; D052006:Bone Morphogenetic Protein Receptors, Type II / Q000378:metabolism*; D002454:Cell Differentiation / Q000502:physiology; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000378:metabolism*; D022163:Clathrin-Coated Vesicles / Q000378:metabolism*; D031541:Fluorescence Resonance Energy Transfer; D006801:Humans; D051379:Mice; D010006:Osteoblasts / Q000502:physiology; D011994:Recombinant Proteins / Q000378:metabolism; D015398:Signal Transduction; D051785:Smad Proteins / Q000378:metabolism
D033962:Adaptor Protein Complex 2; D055396:Bone Morphogenetic Protein 2; D011994:Recombinant Proteins; D051785:Smad Proteins; D052005:Bone Morphogenetic Protein Receptors, Type I; D052006:Bone Morphogenetic Protein Receptors, Type II