title: A novel tumor metastasis suppressor gene LASS2/TMSG1 interacts with vacuolar ATPase through its homeodomain.
abstract: LASS2/TMSG1 was a novel tumor metastasis suppressor gene, which was first cloned by our laboratory from non-metastatic and metastatic cancer cell variants of human prostate carcinoma PC-3M using mRNA differential display in 1999. LASS2/TMSG1 could interact with the C subunit of vacuolar ATPase (V-ATPase, ATP6V0C) and regulate V-ATPase activity. In an attempt to provide molecular mechanism of the interaction between LASS2/TMSG1 and V-ATPase, we constructed four variant transfectants containing different functional domain of LASS2/TMSG1 and stably transfected the variants to human prostate cancer cell line PC-3M-1E8 cell with high metastatic potential. Results showed that there were no obvious differences of V-ATPase expression among different transfected cells and the control. However, V-ATPase activity and intracellular pH was significantly higher in the variant transfectants with Homeodomain of LASS2/TMSG1 than that in the control using the pH-dependent fluorescence probe BECEF/AM. Immunoprecipitation, immunofluorescence and immuno-electron microscope alone or in combination demonstrated the direct interaction of Homeodomain of LASS2/TMSG1 and ATP6V0C. Loss of Homeodomain markedly enhanced the proliferation ability but weakened the apoptotic effect of LASS2/TMSG1 in PC-3M-1E8 cells. These lines of results for the first time contribute to the conclusion that LASS2/TMSG1 could regulate V-ATPase activity and intracellular pH through the direct interaction of its Homeodomain and the C subunit of V-ATPase. Their interaction could play important roles in the apoptosis of tumor cells.
authors.affiliation: Department of Pathology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, PR China.
authors.forename: Wenjuan
authors.initials: W
authors.lastname: Yu
authors.forename: Leiming
authors.initials: L
authors.lastname: Wang
authors.forename: Yuewei
authors.initials: Y
authors.lastname: Wang
authors.forename: Xiaoyan
authors.initials: X
authors.lastname: Xu
authors.forename: Pengcheng
authors.initials: P
authors.lastname: Zou
authors.forename: Miaozi
authors.initials: M
authors.lastname: Gong
authors.forename: Jie
authors.initials: J
authors.lastname: Zheng
authors.forename: Jiangfeng
authors.initials: J
authors.lastname: You
authors.forename: Hua
authors.initials: H
authors.lastname: Wang
authors.forename: Fang
authors.initials: F
authors.lastname: Mei
authors.forename: Fei
authors.initials: F
authors.lastname: Pei
mesh_terms: D017209:Apoptosis; D002453:Cell Cycle; D045744:Cell Line, Tumor; D015972:Gene Expression Regulation, Neoplastic; D016147:Genes, Tumor Suppressor; D006801:Humans; D008297:Male; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D009362:Neoplasm Metastasis / Q000235:genetics*; D011471:Prostatic Neoplasms; D017434:Protein Structure, Tertiary; D034622:RNA Interference; D034741:RNA, Small Interfering; D051049:Sphingosine N-Acyltransferase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D014162:Transfection; D025521:Tumor Suppressor Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D025262:Vacuolar Proton-Translocating ATPases / Q000235:genetics / Q000378:metabolism*
chemical_list: C541389:ATP6V0C protein, human; D008565:Membrane Proteins; D034741:RNA, Small Interfering; D025521:Tumor Suppressor Proteins; C438311:CERS2 protein, human; D051049:Sphingosine N-Acyltransferase; D025262:Vacuolar Proton-Translocating ATPases