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Distinct subcellular localisations of the putative inositol 1,3,4,5-tetrakisphosphate receptors GAP1IP4BP and GAP1m result from the GAP1IP4BP PH domain directing plasma membrane targeting.
Lockyer, P J; Bottomley, J R; Reynolds, J S; McNulty, T J; Venkateswarlu, K; Potter, B V; Dempsey, C E; Cullen, P J.
Afiliação
  • Lockyer PJ; Laboratory of Molecular Studies on Cell Regulation, Department of Biochemistry, School of Medical Sciences, University of Bristol, Bristol BS8 1TD, UK.
Curr Biol ; 7(12): 1007-10, 1997 Dec 01.
Article em En | MEDLINE | ID: mdl-9382842
Inositol 1,3,4,5-tetrakisphosphate (IP4), is a ubiquitous inositol phosphate that has been suggested to function as a second messenger. Recently, we purified and cloned a putative IP4 receptor, termed GAP1(IP4BP)[1], which is also a member of the GAP1 family of GTPase-activating proteins for the Ras family of GTPases. A homologue of GAP1(IP4BP), called GAP1(m), has been identified [2] and here we describe the cloning of a GAP1(m) cDNA from a human circulating-blood cDNA library. We found that a deletion mutant of GAP1(m), in which the putative phospholipid-binding domains (C2A and C2B) have been removed, binds to IP4 with a similar affinity and specificity to that of the corresponding GAP1(IP4BP) mutant. Expression studies of the proteins in either COS-7 or HeLa cells showed that, whereas GAP1(IP4BP) is located solely at the plasma membrane, GAP1(m) seems to have a distinct perinuclear localisation. By mutational analysis, we have shown that the contrast in subcellular distribution of these two closely related proteins may be a function of their respective pleckstrin homology (PH) domains. This difference in localisation has fundamental significance for our understanding of the second messenger functions of IP4.
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Coleções: 01-internacional Base de dados: MEDLINE Limite: Animals / Humans Idioma: En Ano de publicação: 1997 Tipo de documento: Article
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Coleções: 01-internacional Base de dados: MEDLINE Limite: Animals / Humans Idioma: En Ano de publicação: 1997 Tipo de documento: Article