Linked Life Data

11714711

Source:http://linkedlifedata.com/resource/pubmed/id/11714711

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
11
pubmed:dateCreated
2002-3-11
pubmed:abstractText
PIKfyve enzymatic activity is required in maintaining late endocytic membrane integrity. PIKfyve is a dual specificity enzyme that phosphorylates phosphatidylinositol (PtdIns) and PtdIns 3-P at the 5-hydroxyl and unidentified endogenous protein substrate(s). To determine which of these activities (lipid versus protein kinase activity) is responsible for endomembrane homeostasis we analyzed a double mutant PIKfyve(K1999E/K2000E). These substitutions in the putative lipid-substrate activation loop nearly completely abrogated the lipid kinase activity without any significant effect on the protein kinase activity of PIKfyve(K1999E/K2000E). Expression of PIKfyve(K1999E/K2000E) in COS cells induced a dramatic dominant-negative effect in the form of endomembrane swelling and vacuolation. In addition, the lipid-substrate specificity of PIKfyve was modified by introducing single mutations in Lys-1999 or Lys-2000. This yielded proteins with preferentially abrogated synthesis of PtdIns 5-P (PIKfyve(K2000E)) or PtdIns 3,5-P(2) (PIKfyve(K1999E)), of which only the PIKfyve(K1999E) mutant induced the characteristic endomembrane defects upon cell transfection. Furthermore, phosphoinositide microinjection into cells demonstrated a selective ability of PtdIns 3,5-P(2) to correct the endomembrane defects induced by the dominant-negative PIKfyve lipid kinase-deficient mutants. Thus, PtdIns 3,5-P(2) production by PIKfyve is crucial for endomembrane integrity, and Lys-1999 most likely directs the PIKfyve interactions with the 3-phosphate group in PtdIns 3-P.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
15
pubmed:volume
277
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
9206-11
pubmed:dateRevised
2010-11-18
pubmed:meshHeading
pubmed:year
2002
pubmed:articleTitle
Functional dissection of lipid and protein kinase signals of PIKfyve reveals the role of PtdIns 3,5-P2 production for endomembrane integrity.
pubmed:affiliation
Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan 48201, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.