inositol-1,3,4,5-tetrakisphosphate 3-phosphatase activity

Definition

Target type: molecularfunction

Catalysis of the reaction: inositol-1,3,4,5-tetrakisphosphate + H2O = inositol-1,4,5-trisphosphate + phosphate. [GOC:bf, MetaCyc:3.1.3.62-RXN]

Inositol-1,3,4,5-tetrakisphosphate 3-phosphatase activity is a critical enzymatic activity involved in the regulation of intracellular signaling pathways. This activity is catalyzed by enzymes known as inositol polyphosphate 3-phosphatases, which specifically remove the phosphate group at the 3-position of inositol-1,3,4,5-tetrakisphosphate (IP4), converting it to inositol-1,4,5-trisphosphate (IP3). This dephosphorylation reaction plays a crucial role in regulating various cellular processes, including calcium signaling, cell growth, and proliferation.

IP4 is a second messenger molecule that participates in a wide range of signal transduction pathways. Its production is stimulated by various extracellular stimuli, such as hormones, neurotransmitters, and growth factors. Upon activation, IP4 can bind to and activate downstream effector proteins, leading to the initiation of cellular responses.

Inositol polyphosphate 3-phosphatases are responsible for terminating the IP4 signal by removing the phosphate group at the 3-position. This dephosphorylation event results in the formation of IP3, which is a less potent signaling molecule. By reducing the levels of IP4, these phosphatases effectively dampen the signaling cascade and allow for the restoration of cellular homeostasis.

The precise molecular mechanism of IP4 3-phosphatase activity involves the interaction of the enzyme with its substrate, IP4. The enzyme possesses a catalytic site where the phosphate group at the 3-position of IP4 is recognized and bound. Through a series of conformational changes, the enzyme facilitates the hydrolysis of the phosphate group, releasing inorganic phosphate and generating IP3.

The regulation of IP4 3-phosphatase activity is complex and involves a variety of factors, including protein-protein interactions, post-translational modifications, and cellular localization. These regulatory mechanisms ensure that IP4 levels are tightly controlled and that appropriate signaling responses are initiated.

In conclusion, inositol-1,3,4,5-tetrakisphosphate 3-phosphatase activity plays a crucial role in the regulation of cellular signaling by controlling the levels of the second messenger IP4. This enzymatic activity is tightly regulated and contributes to maintaining cellular homeostasis and mediating a variety of cellular processes.'
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Proteins (1)

Compounds (1)