Characterization of the Met326Ile variant of phosphatidylinositol 3-kinase p85alpha
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Characterization of the Met326Ile variant of phosphatidylinositol 3-kinase p85alpha. / Almind, Katrine; Delahaye, Laurent; Hansen, Torben; Van Obberghen, Emmanuel; Pedersen, Oluf; Kahn, C Ronald.
In: Proceedings of the National Academy of Sciences of the United States of America, Vol. 99, No. 4, 19.02.2002, p. 2124-8.Research output: Contribution to journal › Journal article › Research › peer-review
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TY - JOUR
T1 - Characterization of the Met326Ile variant of phosphatidylinositol 3-kinase p85alpha
AU - Almind, Katrine
AU - Delahaye, Laurent
AU - Hansen, Torben
AU - Van Obberghen, Emmanuel
AU - Pedersen, Oluf
AU - Kahn, C Ronald
PY - 2002/2/19
Y1 - 2002/2/19
N2 - Phosphatidylinositol 3-kinase is a key step in the metabolic actions of insulin. Two amino acid substitutions have been identified in the gene for the regulatory subunit of human p85alpha, Met-326Ile, and Asn-330Asp, and the former has been associated with alterations in glucose/insulin homeostasis. When the four human p85alpha proteins were expressed in yeast, a 27% decrease occurred in the level of protein expression of p85alpha(Ile/Asp) (P = 0.03) and a 43% decrease in p85alpha(Ile/Asn) (P = 0.08) as compared with p85alpha(Met/Asp). Both p85alpha(Ile/Asp) and p85alpha(Ile/Asn) also exhibited increased binding to phospho-insulin receptor substrate-1 by 41% and 83%, respectively (P <0.001), as compared with p85alpha(Met/Asp). The expression of p85alpha(Ile) was also slightly decreased and the binding to insulin receptor substrate-1 slightly increased in brown preadipocytes derived from p85alpha knockout mice. Both p85alpha(Met) and p85alpha(Ile) had similar effects on AKT activity and were able to reconstitute differentiation of the preadipocytes, although the triglyceride concentration in fully differentiated adipocytes and insulin-stimulated 2-deoxyglucose uptake were slightly lower than in adipocytes expressing p85alpha(Met). Thus, the Met-326Ile variant of p85alpha is functional for intracellular signaling and adipocyte differentiation but has small alterations in protein expression and activity that could play a role in modifying insulin action.
AB - Phosphatidylinositol 3-kinase is a key step in the metabolic actions of insulin. Two amino acid substitutions have been identified in the gene for the regulatory subunit of human p85alpha, Met-326Ile, and Asn-330Asp, and the former has been associated with alterations in glucose/insulin homeostasis. When the four human p85alpha proteins were expressed in yeast, a 27% decrease occurred in the level of protein expression of p85alpha(Ile/Asp) (P = 0.03) and a 43% decrease in p85alpha(Ile/Asn) (P = 0.08) as compared with p85alpha(Met/Asp). Both p85alpha(Ile/Asp) and p85alpha(Ile/Asn) also exhibited increased binding to phospho-insulin receptor substrate-1 by 41% and 83%, respectively (P <0.001), as compared with p85alpha(Met/Asp). The expression of p85alpha(Ile) was also slightly decreased and the binding to insulin receptor substrate-1 slightly increased in brown preadipocytes derived from p85alpha knockout mice. Both p85alpha(Met) and p85alpha(Ile) had similar effects on AKT activity and were able to reconstitute differentiation of the preadipocytes, although the triglyceride concentration in fully differentiated adipocytes and insulin-stimulated 2-deoxyglucose uptake were slightly lower than in adipocytes expressing p85alpha(Met). Thus, the Met-326Ile variant of p85alpha is functional for intracellular signaling and adipocyte differentiation but has small alterations in protein expression and activity that could play a role in modifying insulin action.
KW - Adipocytes
KW - Adipose Tissue, Brown
KW - Animals
KW - Cattle
KW - Codon
KW - DNA, Complementary
KW - Dose-Response Relationship, Drug
KW - Genes, Reporter
KW - Glucose
KW - Humans
KW - Insulin
KW - Methionine
KW - Mice
KW - Models, Genetic
KW - Phosphatidylinositol 3-Kinases
KW - Phosphorylation
KW - Plasmids
KW - Protein Binding
KW - Rats
KW - Signal Transduction
KW - Time Factors
KW - Triglycerides
KW - Two-Hybrid System Techniques
U2 - 10.1073/pnas.042688799
DO - 10.1073/pnas.042688799
M3 - Journal article
C2 - 11842213
VL - 99
SP - 2124
EP - 2128
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
SN - 0027-8424
IS - 4
ER -
ID: 38454425