title: BIT/SHPS-1 promotes antiapoptotic effect of BDNF on low potassium-induced cell death of cultured cerebellar granule neurons.
abstract: Brain immunoglobulin-like molecule with tyrosine-based activation motifs/SHP substrate 1 (BIT/SHPS-1) is a neuronal adhesion molecule that is highly expressed in cerebellar granule neurons (CGNs); however its function in CGNs remains unclear. Our previous studies indicated that BIT/SHPS-1 is able to modulate the antiapoptotic effect of brain-derived neurotrophic factor (BDNF) on CNS neurons by cell type-specific mechanisms. In this article, we have studied the role of BIT/SHPS-1 in the antiapoptotic function of BDNF on low potassium (LK)-induced cell death of cultured CGNs which is an in vitro model system of neuronal apoptosis during brain development. Cultured rat CGNs were transduced with wild-type rat BIT/SHPS-1 (BIT/SHPS-1(WT)), its 4F-mutant (BIT/SHPS-1(4F), in which all cytoplasmic tyrosine residues were substituted with phenylalanine), or nuclear localization signal-attached beta-galactosidase (NLS-LacZ, as control)-expressing adenoviruses. Expression of BIT/SHPS-1(WT) and BIT/SHPS-1(4F) alone did not affect steady-state cell viability. Tyrosine phosphorylation of BIT/SHPS-1 was only detected in BIT/SHPS-1(WT)-expressing cultures in the presence and the absence of BDNF. When subjected to LK in the presence of BDNF, BIT/SHPS-1(WT)- and BIT/SHPS-1(4F)-expressing cultures showed a significant resistance to cell death, while the control virus-transfected culture did not. In addition, a phosphatidylinositol 3-kinase (PI3-K) inhibitor, LY294002, attenuated the antiapoptotic effect of BDNF on BIT/SHPS-1(WT)-, and BIT/SHPS-1(4F)-expressing cultures. These results demonstrated that in both tyrosine phosphorylation-independent and PI3-K-dependent manners, BIT/SHPS-1 promotes the antiapoptotic effect of BDNF on the LK-induced cell death of CGNs.
authors.affiliation: Research Institute for Cell Engineering (RICE), National Institute of Advanced Industrial Science and Technology (AIST), Ikeda 563-8577, Japan. h-koshimizu@umin.ac.jp
authors.forename: Hisatsugu
authors.initials: H
authors.lastname: Koshimizu
authors.forename: Shingo
authors.initials: S
authors.lastname: Suzuki
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Araki
authors.forename: Masashi
authors.initials: M
authors.lastname: Yamada
authors.forename: Masami
authors.initials: M
authors.lastname: Kojima
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Hatanaka
mesh_terms: D000818:Animals; D019208:Brain-Derived Neurotrophic Factor / Q000494:pharmacology*; D016923:Cell Death / Q000187:drug effects*; D002470:Cell Survival / Q000187:drug effects; D002531:Cerebellum / Q000166:cytology*; D002867:Chromones / Q000494:pharmacology; D057809:HEK293 Cells; D006801:Humans; D009025:Morpholines / Q000494:pharmacology; D009474:Neurons / Q000166:cytology / Q000187:drug effects* / Q000502:physiology*; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D000081082:Phosphoinositide-3 Kinase Inhibitors; D011188:Potassium / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D011971:Receptors, Immunologic / Q000235:genetics / Q000378:metabolism*
chemical_list: D019208:Brain-Derived Neurotrophic Factor; D002867:Chromones; D009025:Morpholines; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; D011188:Potassium; D011971:Receptors, Immunologic; C501924:Sirpa protein, rat; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one