Alternative splicing affecting the SH3A domain controls the binding properties of intersectin 1 in neurons.
Intersectin 1 (ITSN1) is a conserved adaptor protein implicated in endocytosis, regulation of actin cytoskeleton rearrangements and mitogenic signaling. Its expression is characterized by multiple alternative splicing. Here we show neuron-specific expression of ITSN1 isoforms containing exon 20, which encodes five amino acid residues in the first SH3 domain (SH3A). In vitro binding experiments demonstrated that inclusion of exon 20 changes the binding properties of the SH3A domain. Endocytic proteins dynamin 1 and synaptojanin 1 as well as GTPase-activating protein CdGAP bound the neuron-specific variant of the SH3A domain with higher affinity than ubiquitously expressed SH3A. In contrast, SOS1, a guanine nucleotide exchange factor for Ras, and the ubiquitin ligase Cbl mainly interact with the ubiquitously expressed isoform. These results demonstrate that alternative splicing leads to the formation of two pools of ITSN1 with potentially different properties in neurons, affecting ITSN1 function as adaptor protein.
Institute of Molecular Biology and Genetics, 150 Zabolotnogo Street, Kyiv 03143, Ukraine. l.o.tsyba@imbg.org.ua
Liudmyla
L
Tsyba
Tetyana
T
Gryaznova
Oleksandr
O
Dergai
Mykola
M
Dergai
Inessa
I
Skrypkina
Sergiy
S
Kropyvko
Oleksiy
O
Boldyryev
Oleksii
O
Nikolaienko
Olga
O
Novokhatska
Alla
A
Rynditch
D033942:Adaptor Proteins, Vesicular Transport / Q000235:genetics* / Q000378:metabolism*; D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D002460:Cell Line; D034284:Dynamin I / Q000378:metabolism; D005091:Exons; D020690:GTPase-Activating Proteins / Q000378:metabolism; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D009474:Neurons / Q000378:metabolism*; D010750:Phosphoproteins / Q000378:metabolism; D010744:Phosphoric Monoester Hydrolases / Q000378:metabolism; D020033:Protein Isoforms / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D018909:src Homology Domains; D000099182:Phosphoinositide 5-Phosphatases
D033942:Adaptor Proteins, Vesicular Transport; D034284:Dynamin I; D020690:GTPase-Activating Proteins; D010750:Phosphoproteins; D010744:Phosphoric Monoester Hydrolases; D020033:Protein Isoforms; D012333:RNA, Messenger; D000099182:Phosphoinositide 5-Phosphatases; C514543:ARHGAP31 protein, human; C115919:intersectin 1