title: rSac3, a novel Sac domain phosphoinositide phosphatase, promotes neurite outgrowth in PC12 cells.
abstract: Sac domain-containing proteins belong to a newly identified family of phosphoinositide phosphatases (the PIPPase family). Despite well-characterized enzymatic activity, the biological functions of this mammalian Sac domain PIPPase family remain largely unknown. We identified a novel Sac domain-containing protein, rat Sac3 (rSac3), which is widely expressed in various tissues and localized to the endoplasmic reticulum, Golgi complex and recycling endosomes. rSac3 displays PIPPase activity with PI(3)P, PI(4)P and PI(3,5)P(2) as substrates in vitro, and a mutation in the catalytic core of the Sac domain abolishes its enzymatic activity. The expression of rSac3 is upregulated during nerve growth factor (NGF)-stimulated PC12 cell neuronal differentiation, and overexpression of this protein promotes neurite outgrowth in PC12 cells. Conversely, inhibition of rSac3 expression by antisense oligonucleotides reduces neurite outgrowth of NGF-stimulated PC12 cells, and the active site mutation of rSac3 eliminates its neurite-outgrowth-promoting activity. These results indicate that rSac3 promotes neurite outgrowth in differentiating neurons through its PIPPase activity, suggesting that Sac domain PIPPase proteins may participate in forward membrane trafficking from the endoplasmic reticulum and Golgi complex to the plasma membrane, and may function as regulators of this crucial process of neuronal cell growth and differentiation.
authors.affiliation: Laboratory of Molecular Cell Biology and Key Laboratory of Stem Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yue yang Road, Shanghai 200031, China.
authors.forename: Yiyuan
authors.initials: Y
authors.lastname: Yuan
authors.forename: Xiang
authors.initials: X
authors.lastname: Gao
authors.forename: Ning
authors.initials: N
authors.lastname: Guo
authors.forename: Hui
authors.initials: H
authors.lastname: Zhang
authors.forename: Zhiqin
authors.initials: Z
authors.lastname: Xie
authors.forename: Meilei
authors.initials: M
authors.lastname: Jin
authors.forename: Baoming
authors.initials: B
authors.lastname: Li
authors.forename: Lei
authors.initials: L
authors.lastname: Yu
authors.forename: Naihe
authors.initials: N
authors.lastname: Jing
mesh_terms: D000818:Animals; D019556:COS Cells; D002522:Chlorocebus aethiops; D004721:Endoplasmic Reticulum / Q000201:enzymology* / Q000235:genetics; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects / Q000502:physiology*; D006056:Golgi Apparatus / Q000201:enzymology* / Q000235:genetics; D020932:Nerve Growth Factor / Q000494:pharmacology; D016501:Neurites / Q000201:enzymology*; D020319:Oligodeoxyribonucleotides, Antisense / Q000494:pharmacology; D016716:PC12 Cells; D010744:Phosphoric Monoester Hydrolases / Q000096:biosynthesis* / Q000235:genetics; D017434:Protein Structure, Tertiary / Q000235:genetics; D021381:Protein Transport / Q000187:drug effects / Q000502:physiology; D051381:Rats; D015854:Up-Regulation / Q000187:drug effects / Q000502:physiology; D000099182:Phosphoinositide 5-Phosphatases
chemical_list: D020932:Nerve Growth Factor; D020319:Oligodeoxyribonucleotides, Antisense; D010744:Phosphoric Monoester Hydrolases; D000099182:Phosphoinositide 5-Phosphatases; C527237:Fig4 protein, rat