A new member of the amphiphysin family connecting endocytosis and signal transduction pathways.
Src homology 3 (SH3) domains are conserved modules which participate in protein interaction by recognizing proline-rich motifs on target molecules. To identify new SH3-containing proteins, we performed a two-hybrid screen with a proline-rich region of human SOS-1. One of the specific SOS-1 interacting clones that were isolated from a mouse brain cDNA library defines a new protein that was named amphiphysin 2 because of its homology to the previously reported amphiphysin. Amphiphysin 2 is expressed in a number of mouse tissues through multiple RNA transcripts. Here, we report the amino acid sequence of a brain form of amphiphysin 2 (BRAMP2) encoded by a 2. 5-kilobase mRNA. BRAMP2 associates in vitro with elements of the endocytosis machinery such as alpha-adaptin and dynamin. On a biosensor surface, the BRAMP2/dynamin interaction appeared to be direct and partly dependent on a proline-rich sequence of dynamin. Association with dynamin was also observed in PC12 cells after cell stimulation with nerve growth factor, suggesting that amphiphysin 2 may be connected to receptor-dependent signaling pathways. This hypothesis is strengthened by the ability of BRAMP2 to interact with the p21(ras) exchange factor SOS, in vitro, as a possible point of interconnection between the endocytic and signaling pathways.
Leprince
C
C
INSERM U248, Institut Curie, 26 rue d'Ulm, 75231 Paris Cedex 05, France. leprince@curie.fr
Romero
F
F
Cussac
D
D
Vayssiere
B
B
Berger
R
R
Tavitian
A
A
Camonis
J H
JH
D033965:Adaptor Protein Complex alpha Subunits; D048868:Adaptor Proteins, Signal Transducing; D033942:Adaptor Proteins, Vesicular Transport; D000595:Amino Acid Sequence; D000818:Animals; D018076:DNA, Complementary; D034281:Dynamins; D004705:Endocytosis; D005656:Fungal Proteins / Q000378:metabolism; D020558:GTP Phosphohydrolases / Q000378:metabolism; D006801:Humans; D008297:Male; D008565:Membrane Proteins / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D016716:PC12 Cells; D051381:Rats; D011956:Receptors, Cell Surface / Q000378:metabolism; D012097:Repressor Proteins / Q000378:metabolism; D020837:SOS1 Protein; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction; D025521:Tumor Suppressor Proteins
D033965:Adaptor Protein Complex alpha Subunits; D048868:Adaptor Proteins, Signal Transducing; D033942:Adaptor Proteins, Vesicular Transport; C109221:Bin1 protein, mouse; D018076:DNA, Complementary; D005656:Fungal Proteins; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D011956:Receptors, Cell Surface; D012097:Repressor Proteins; D020837:SOS1 Protein; D025521:Tumor Suppressor Proteins; D020558:GTP Phosphohydrolases; D034281:Dynamins