High impact information on PIK3R4

• In vitro, the head domains of CLIP-170 and of p150 Glued bind more efficiently to tyrosinated microtubules than to detyrosinated polymers [1].
• Here, we show that fasciata1-4 (fas1-4), a new allele of the Arabidopsis fas1 mutant defective in the p150 subunit of CAF-1, has a severe developmental phenotype, reduced heterochromatin content, and a more open conformation of euchromatin [2].
• Vps34p is a phosphatidylinositol 3-kinase that is part of a membrane-associated complex with the Vps15p protein kinase [3].
• Two-hybrid mapping experiments indicated that two separate regions of Vps15p were required for the association with Vps34p; they are the N-terminal protein kinase domain and a set of three tandem repeats of about 39 amino acids each [3].
• These Vps15p repeat elements are similar in sequence to the HEAT motifs that have been implicated in protein interactions in other proteins, including the Huntingtin protein [3].

Biological context of PIK3R4

• Northern blot analysis showed a ubiquitous tissue distribution for p150 similar to that previously observed with PtdIns 3-kinase [4].
• Our data define p150 as a new target for this kinase with implications for the coordination between DNA replication and CAF1 functions [5].
• Five of the ten LpCBF genes were assigned to the genetic linkage map using the p150/112 reference mapping population [6].

Anatomical context of PIK3R4

• Cleavage of MP1 and release of a 150-kDa intermediate, p150, are likely to be important for embedding the replicase complex in cellular membranes [7].
• Immuno-EM revealed that these sheets, apparently in contact with the cytosol, contained both P150 and P90, as well as dsRNA, and thus could be two-dimensional arrays of functional viral replicases [8].

Associations of PIK3R4 with chemical compounds

• Characterization of p150, an adaptor protein for the human phosphatidylinositol (PtdIns) 3-kinase. Substrate presentation by phosphatidylinositol transfer protein to the p150.Ptdins 3-kinase complex [4].
• The C terminus of the Vps34p phosphoinositide 3-kinase is necessary and sufficient for the interaction with the Vps15p protein kinase [3].

Analytical, diagnostic and therapeutic context of PIK3R4

• Native immunoprecipitation experiments confirm that Sec13p exists in a complex with p150 in wild type cells [9].
• Confocal microscopy showed that the RUB replicase components P90 and P150 localized to CPVs, as did double-stranded RNA (dsRNA), a marker for RNA synthesis [8].

References