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Full-Text Articles in Biochemistry, Biophysics, and Structural Biology

The Role Of Inositol Polyphosphate-4-Phosphatase Type Ii B (Inpp4b) In Obese Models And Endocrine Cancers, Manqi Zhang Nov 2019

The Role Of Inositol Polyphosphate-4-Phosphatase Type Ii B (Inpp4b) In Obese Models And Endocrine Cancers, Manqi Zhang

FIU Electronic Theses and Dissertations

INPP4B is a dual-specificity phosphatase and a tumor suppressor in prostate and breast cancers. Progression of the prostate and breast cancers depends on the androgen receptor (AR) or estrogen receptor alpha (ERα) signaling, respectively. In this work we demonstrated that INPP4B reprograms ERα transcriptional activity in breast cancer. INPP4B maintains expression and protein levels of progesterone receptor (PR), an ERα direct target gene required for mammary gland development. Consistently we demonstrated that Inpp4b knockout severely impairs lateral branching in the mammary gland of maturing virgin females. In advanced prostate cancer, activation and transcriptional reprogramming of AR frequently coincides with the …


Transition State Interactions In A Promiscuous Enzyme: Sulfate And Phosphate Monoester Hydrolysis By Pseudomonas Aeruginosa Arylsulfatase, Bert Van Loo, Ryan Berry, Usa Boonyuen, Mark F. Mohamed, Marko Golicnik, Alvan C. Hengge, Florian Hollfelder Feb 2019

Transition State Interactions In A Promiscuous Enzyme: Sulfate And Phosphate Monoester Hydrolysis By Pseudomonas Aeruginosa Arylsulfatase, Bert Van Loo, Ryan Berry, Usa Boonyuen, Mark F. Mohamed, Marko Golicnik, Alvan C. Hengge, Florian Hollfelder

Chemistry and Biochemistry Faculty Publications

Pseudomonas aeruginosa arylsulfatase (PAS) hydrolyses sulfate and, promiscuously, phosphate monoesters. Enzyme-catalyzed sulfate transfer is crucial to a wide variety of biological processes, but detailed studies of the mechanistic contributions to its catalysis are lacking. We present linear free energy relationships (LFERs) and kinetic isotope effects (KIEs) of PAS and active site mutants that suggest a key role for leaving group (LG) stabilization. In LFERs PASWT has a much less negative Brønsted coefficient (ßleaving group obs-Enz=-0.33) than the uncatalyzed reaction (ßleaving group obs=-1.81). This situation is diminished when cationic active site groups are exchanged for alanine. …