4ikc
From Proteopedia
Crystal Structure of catalytic domain of PTPRQ
Structural highlights
DiseasePTPRQ_HUMAN Autosomal recessive nonsyndromic sensorineural deafness type DFNB. The disease is caused by mutations affecting the gene represented in this entry. FunctionPTPRQ_HUMAN Phosphatidylinositol phosphatase required for auditory function. May act by regulating the level of phosphatidylinositol 4,5-bisphosphate (PIP2) level in the basal region of hair bundles. Can dephosphorylate a broad range of phosphatidylinositol phosphates, including phosphatidylinositol 3,4,5-trisphosphate and most phosphatidylinositol monophosphates and diphosphates. Phosphate can be hydrolyzed from the D3 and D5 positions in the inositol ring. Has low tyrosine-protein phosphatase activity; however, the relevance of such activity in vivo is unclear. Plays an important role in adipogenesis of mesenchymal stem cells (MSCs). Regulates the phosphorylation state of AKT1 by suppressing the phosphatidylinositol 3,4,5-trisphosphate (PIP3) level in MSCs and preadipocyte cells.[1] Publication Abstract from PubMedUnlike other classical protein tyrosine phosphatases (PTPs), PTPRQ (PTP receptor type Q) has dephosphorylating activity towards phosphatidylinositide (PI) substrates. Here, the structure of the catalytic domain of PTPRQ was solved at 1.56 A resolution. Overall, PTPRQ adopts a tertiary fold typical of other classical PTPs. However, the disordered M6 loop of PTPRQ surrounding the catalytic core and the concomitant absence of interactions of this loop with residues in the PTP loop results in a flat active-site pocket. On the basis of structural and biochemical analyses, it is proposed that this structural feature might facilitate the accommodation of large substrates, making it suitable for the dephosphorylation of PI substrates. Moreover, subsequent kinetic experiments showed that PTPRQ has a strong preferences for PI(3,4,5)P3 over other PI substrates, suggesting that its regulation of cell survival and proliferation reflects downregulation of Akt signalling. Structural basis for the dephosphorylating activity of PTPRQ towards phosphatidylinositide substrates.,Yu KR, Kim YJ, Jung SK, Ku B, Park H, Cho SY, Jung H, Chung SJ, Bae KH, Lee SC, Kim BY, Erikson RL, Ryu SE, Kim SJ Acta Crystallogr D Biol Crystallogr. 2013 Aug;69(Pt 8):1522-9. doi:, 10.1107/S0907444913010457. Epub 2013 Jul 19. PMID:23897475[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
|
Categories: Homo sapiens | Large Structures | Kim SJ | Ryu SE | Yu KR