Splice variant 3, but not 2 of receptor protein-tyrosine phosphatase sigma can mediate stimulation of insulin-secretion by alpha-latrotoxin.
Alpha-latrotoxin (alpha-LTX) binds to several cell surface receptors including receptor protein-tyrosine phosphatase sigma (RPTPsigma). Here we demonstrate that transient overexpression of the short splice variant 3 conferred alpha-LTX induced secretion to hamster insulinoma (HIT-15) cells. In contrast, the long splice variant 2 containing four additional extracellular fibronectin-III domains was inactive in secretion or in a single cell assay. Toxin-sensitive (MIN6) and toxin-insensitive (HIT-T15) insulinoma cell lines as well as PC12 cells expressed similar amounts of endogenous short RPTPsigma splice variant suggesting that this receptor does not play a role for toxin-sensitivity.
Institut Européen de Chimie et Biologie, JE 2390, F-33607 Bordeaux/Pessac, France.
Sophie
S
Lajus
Jochen
J
Lang
D000818:Animals; D045744:Cell Line, Tumor; D006224:Cricetinae; D005089:Exocytosis; D007328:Insulin / Q000378:metabolism*; D016716:PC12 Cells; D051571:Protein Kinase C-alpha / Q000378:metabolism; D017027:Protein Tyrosine Phosphatases / Q000235:genetics / Q000378:metabolism*; D012326:RNA Splicing; D051381:Rats; D054623:Receptor-Like Protein Tyrosine Phosphatases, Class 2; D015398:Signal Transduction; D013111:Spider Venoms / Q000494:pharmacology*; D014162:Transfection
D007328:Insulin; D013111:Spider Venoms; C020763:alpha-latrotoxin; D051571:Protein Kinase C-alpha; D017027:Protein Tyrosine Phosphatases; D054623:Receptor-Like Protein Tyrosine Phosphatases, Class 2