INPP4B
INPP4B (inositol polyphosphate-4-phosphatase type II B) is a phosphoinositide phosphatase that removes the 4-position phosphate from inositol 3,4-bisphosphate and related substrates. It antagonises PI3K-AKT signalling and is linked to tumour suppressor function. Browse Assay Genie's current range of INPP4B research reagents below, or read on for the biology behind the target.
INPP4B catalyses the hydrolysis of the 4-position phosphate of phosphatidylinositol 3,4-bisphosphate, inositol 1,3,4-trisphosphate and inositol 3,4-trisphosphate. By dephosphorylating phosphoinositides in this way, it antagonises the PI3K-AKT/PKB signalling pathway and so modulates cell cycle progression and cell survival. It also acts in the late stages of macropinocytosis, where it dephosphorylates phosphatidylinositol 3,4-bisphosphate in membrane ruffles.
The lipid phosphatase activity of the enzyme is critical for its tumour suppressor function, which makes the INPP4B protein a frequent subject in studies of phosphoinositide signalling and cell growth control. The NCBI Gene summary describes the INPP4B gene as encoding the type II enzyme, one of the enzymes involved in phosphatidylinositol signalling pathways, which removes the phosphate group at position 4 of the inositol ring from inositol 3,4-bisphosphate. The protein belongs to the inositol 3,4-bisphosphate 4-phosphatase family. HGNC places it in the C2 domain containing and phosphoinositide phosphatases gene groups. Mouse and rat orthologues are named Inpp4b.
The gene was previously named inositol polyphosphate-4-phosphatase, type II, 105kD (also written 105kDa), and it is distinct from the type I enzyme, INPP4A. RefSeq notes that there is limited data to suggest that the human type II enzyme is subject to alternative splicing, as has been established for the type I enzyme.
INPP4B dephosphorylates phosphoinositides to antagonise PI3K-AKT/PKB signalling, making it a useful node for studying pathway regulation.
Its lipid phosphatase activity is critical for tumour suppressor function, linking INPP4B to studies of growth control.
By modulating phosphoinositide levels, INPP4B influences cell cycle progression and cell survival.
INPP4B acts in the late stages of macropinocytosis by dephosphorylating phosphatidylinositol 3,4-bisphosphate in membrane ruffles.
INPP4B is a lipid phosphatase that hydrolyses the 4-position phosphate of phosphatidylinositol 3,4-bisphosphate, inositol 1,3,4-trisphosphate and inositol 3,4-trisphosphate. Through this activity it antagonises PI3K-AKT/PKB signalling, affecting cell cycle progression and cell survival, and it contributes to late macropinocytosis.
The HGNC full name is inositol polyphosphate-4-phosphatase type II B, and UniProt lists inositol polyphosphate 4-phosphatase type II. Earlier names included inositol polyphosphate-4-phosphatase, type II, 105kD. No alternative gene symbols are recorded. The related type I enzyme is a separate gene, INPP4A.
Mouse and rat both have an orthologue named Inpp4b, so rodent models can be used to study it; check the datasheet of any product for its validated reactivity. UniProt states that its lipid phosphatase activity is critical for tumour suppressor function.
Other inositol polyphosphate phosphatases and phosphoinositide-signalling enzymes with products at Assay Genie.
Gene and protein annotations from HGNC, NCBI Gene and UniProt O15327; product specifications from Assay Genie datasheets.