The glioma-associated protein SETA interacts with AIP1/Alix and ALG-2 and modulates apoptosis in astrocytes.
Expression of the src homology 3 (SH3) domain-containing expressed in tumorigenic astrocytes (SETA) gene is associated with the tumorigenic state in astrocytes. SETA encodes a variety of adapter proteins containing either one or two SH3 domains, as suggested by the sequence heterogeneity of isolated cDNAs. Using both SH3 domains in a yeast two-hybrid screen of a glial progenitor cell cDNA library, we isolated the rat homolog of the ALG-2-interacting protein 1 or ALG-2-interacting protein X (AIP1/Alix). In vitro confrontation experiments showed that the SH3-N domain of SETA interacted with the proline-rich C terminus of AIP1. In co-immunoprecipitation experiments, SETA and AIP1 interacted and could form a complex with apoptosis-linked gene 2 protein. Endogenous SETA and AIP1 proteins showed similar patterns of staining in primary rat astrocytes. Misexpression of a variety of SETA protein isoforms in these astrocytes revealed that they localized to the actin cytoskeleton. Furthermore, SETA proteins containing the SH3-N domain were able to sensitize astrocytes to apoptosis induced by UV irradiation. Expression of the isolated SH3-N domain had the greatest effect in these experiments, indicating that interference in the interaction between endogenous SETA and AIP1 sensitizes astrocytes to apoptosis in response to DNA damage.
Chen
B
B
Department of Anatomy and Division of Neurosurgery, P.O. Box 980709, Virginia Commonwealth University, Richmond, Virginia 23298, USA.
Borinstein
S C
SC
Gillis
J
J
Sykes
V W
VW
Bogler
O
O
D000199:Actins / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D017209:Apoptosis / Q000502:physiology*; D051017:Apoptosis Regulatory Proteins; D001253:Astrocytes / Q000166:cytology* / Q000528:radiation effects; D002135:Calcium-Binding Proteins / Q000378:metabolism*; D002352:Carrier Proteins / Q000378:metabolism*; D018076:DNA, Complementary; D008969:Molecular Sequence Data; D009363:Neoplasm Proteins / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D009419:Nerve Tissue Proteins / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D011485:Protein Binding; D051381:Rats; D017386:Sequence Homology, Amino Acid; D020798:Two-Hybrid System Techniques; D014466:Ultraviolet Rays; D014981:Xenopus; D018909:src Homology Domains
D000199:Actins; D051017:Apoptosis Regulatory Proteins; D002135:Calcium-Binding Proteins; D002352:Carrier Proteins; D018076:DNA, Complementary; D009363:Neoplasm Proteins; D009419:Nerve Tissue Proteins; C490815:Pdcd6 protein, mouse; C492144:Pdcd6ip protein, mouse; C492143:Pdcd6ip protein, rat; C411889:Sh3kbp1 protein, rat