Mint 3: a ubiquitous mint isoform that does not bind to munc18-1 or -2.
Mint 1 and 2 are proteins that bind to munc18-1, an essential component of the synaptic vesicle fusion machinery, and are detectably expressed only in neurons [Okamoto and Südhof, J. Biol. Chem. 272, 31459-31464 (1997)]. Mint 1 and 2 are composed of a variable N-terminal region that includes a conserved munc18-1-binding site, and a constant C-terminal region that contains one PTB and two PDZ domains. We have now identified a third mint isoform, mint 3. Similar to mint 1 and 2, the C-terminal half of mint 3 is composed of one PTB domain and two PDZ domains. However, in contrast to mint 1 and 2, mint 3 lacks an N-terminal munc18-binding domain and does not interact with munc18-1 in yeast two-hybrid assays. Mint 3 is ubiquitously expressed in all tissues, with lowest levels in brain and testis whereas mint 1 and 2 appear to be brain-specific. Our data suggest that mints form a diverse family of proteins with specialized neuronal and ubiquitous isoforms.
Okamoto
M
M
Center for Basic Neuroscience, Department of Molecular Genetics, The University of Texas Southwestern Medical School, Dallas 75235, USA.
Südhof
T C
TC
D048868:Adaptor Proteins, Signal Transducing; D000595:Amino Acid Sequence; D000818:Animals; D000954:Antigens, Surface / Q000378:metabolism; D015820:Cadherins; D002352:Carrier Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D003001:Cloning, Molecular; D006801:Humans; D008565:Membrane Proteins; D051379:Mice; D008969:Molecular Sequence Data; D051938:Munc18 Proteins; D009419:Nerve Tissue Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D020033:Protein Isoforms; D011506:Proteins / Q000378:metabolism*; D051381:Rats; D016415:Sequence Alignment; D013572:Synaptic Vesicles / Q000378:metabolism; D050827:Syntaxin 1; D014018:Tissue Distribution; D033921:Vesicular Transport Proteins
C079091:APBA1 protein, human; C491636:APBA2 protein, human; C117536:APBA3 protein, human; D048868:Adaptor Proteins, Signal Transducing; D000954:Antigens, Surface; C513072:Apba1 protein, mouse; C513071:Apba1 protein, rat; C491635:Apba2 protein, mouse; C109650:Apba2 protein, rat; C485530:Apba3 protein, mouse; C485532:Apba3 protein, rat; D015820:Cadherins; D002352:Carrier Proteins; D008565:Membrane Proteins; D051938:Munc18 Proteins; D009419:Nerve Tissue Proteins; D020033:Protein Isoforms; D011506:Proteins; C497937:STXBP1 protein, human; C497938:Stxbp1 protein, mouse; C497939:Stxbp1 protein, rat; D050827:Syntaxin 1; D033921:Vesicular Transport Proteins