SAP90, a rat presynaptic protein related to the product of the Drosophila tumor suppressor gene dlg-A.
A novel synapse-associated protein, SAP90, accumulates around the axon hillock of Purkinje cells in rat cerebellum. By immuno-electron microscopy, SAP90 has been localized to the presynaptic termini of basket cells forming inhibitory, gamma-aminobutyric acid (GABA)ergic synapses onto Purkinje cell axon hillocks. The amino acid sequence for SAP90 has been deduced from the nucleotide sequence of a series of overlapping cDNA clones. SAP90 is related to the gene product encoded by the Drosophila tumor suppressor gene dlg-A. SAP90 and the dlg-A product share an overall sequence identity of 54%. Three distinct domains can be identified: (i) a potential cytoskeletal region consisting of three repeats of 90 amino acids in length, (ii) a domain with similarity to SH3, a putative regulatory motif found in the src family of non-receptor protein tyrosine kinases and several proteins associated with the cortical cytoskeleton, and (iii) a carboxyl-terminal domain homologous to yeast guanylate kinase. These features suggest a possible role for SAP90 in a guanine nucleotide-mediated signal transduction pathway at a subset of GABAergic synapses in the rat cerebellum.
Kistner
U
U
Center for Molecular Neurobiology, University of Hamburg, Germany.
Wenzel
B M
BM
Veh
R W
RW
Cases-Langhoff
C
C
Garner
A M
AM
Appeltauer
U
U
Voss
B
B
Gundelfinger
E D
ED
Garner
C C
CC
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002531:Cerebellum / Q000378:metabolism; D004247:DNA; D004330:Drosophila; D029721:Drosophila Proteins; D016147:Genes, Tumor Suppressor; D007301:Insect Hormones / Q000235:genetics*; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000235:genetics* / Q000378:metabolism; D012313:RNA / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D015183:Restriction Mapping; D000074407:SAP90-PSD95 Associated Proteins; D017386:Sequence Homology, Amino Acid; D013569:Synapses / Q000378:metabolism*; D025521:Tumor Suppressor Proteins
D029721:Drosophila Proteins; D007301:Insect Hormones; D009419:Nerve Tissue Proteins; D000074407:SAP90-PSD95 Associated Proteins; D025521:Tumor Suppressor Proteins; C070350:dlg1 protein, Drosophila; D012313:RNA; D004247:DNA