Site-Specific Phosphorylation of Lys-Ser-Pro Repeat Peptides from Neurofilament H by Cyclin-Dependent Kinase 5:  Structural Basis for Substrate Recognition

Biochemistry ◽  
1998 ◽  
Vol 37 (14) ◽  
pp. 4759-4766 ◽  
Author(s):  
Pushkar Sharma ◽  
Joseph J. Barchi, ◽  
Xiaolin Huang ◽  
Niranjana D. Amin ◽  
Howard Jaffe ◽  
...  
2016 ◽  
Vol 113 (44) ◽  
pp. 12438-12443 ◽  
Author(s):  
Min Kyung Kim ◽  
Sun Joo Oh ◽  
Byung-Gil Lee ◽  
Hyun Kyu Song

The first step of the hierarchically organized Arg/N-end rule pathway of protein degradation is deamidation of the N-terminal glutamine and asparagine residues of substrate proteins to glutamate and aspartate, respectively. These reactions are catalyzed by the N-terminal amidase (Nt-amidase) Nta1 in fungi such as Saccharomyces cerevisiae, and by the glutamine-specific Ntaq1 and asparagine-specific Ntan1 Nt-amidases in mammals. To investigate the dual specificity of yeast Nta1 (yNta1) and the importance of second-position residues in Asn/Gln-bearing N-terminal degradation signals (N-degrons), we determined crystal structures of yNta1 in the apo state and in complex with various N-degron peptides. Both an Asn-peptide and a Gln-peptide fit well into the hollow active site pocket of yNta1, with the catalytic triad located deeper inside the active site. Specific hydrogen bonds stabilize interactions between N-degron peptides and hydrophobic peripheral regions of the active site pocket. Key determinants for substrate recognition were identified and thereafter confirmed by using structure-based mutagenesis. We also measured affinities between yNta1 (wild-type and its mutants) and specific peptides, and determined KM and kcat for peptides of each type. Together, these results elucidate, in structural and mechanistic detail, specific deamidation mechanisms in the first step of the N-end rule pathway.


2005 ◽  
Vol 25 (1_suppl) ◽  
pp. S309-S309
Author(s):  
Svetlana Pundik ◽  
W David Lust ◽  
Jose Valerio ◽  
Michael Buczek ◽  
Randall D York ◽  
...  

Author(s):  
Sowmya Suri ◽  
Rumana Waseem ◽  
Seshagiri Bandi ◽  
Sania Shaik

A 3D model of Cyclin-dependent kinase 5 (CDK5) (Accession Number: Q543f6) is generated based on crystal structure of P. falciparum PFPK5-indirubin-5-sulphonate ligand complex (PDB ID: 1V0O) at 2.30 Å resolution was used as template. Protein-ligand interaction studies were performed with flavonoids to explore structural features and binding mechanism of flavonoids as CDK5 (Cyclin-dependent kinase 5) inhibitors. The modelled structure was selected on the basis of least modeler objective function. The model was validated by PROCHECK. The predicted 3D model is reliable with 93.0% of amino acid residues in core region of the Ramachandran plot. Molecular docking studies with flavonoids viz., Diosmetin, Eriodictyol, Fortuneletin, Apigenin, Ayanin, Baicalein, Chrysoeriol and Chrysosplenol-D with modelled protein indicate that Diosmetin is the best inhibitor containing docking score of -8.23 kcal/mol. Cys83, Lys89, Asp84. The compound Diosmetin shows interactions with Cys83, Lys89, and Asp84.


Biomedicines ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 832
Author(s):  
Michishige Terasaki ◽  
Hironori Yashima ◽  
Yusaku Mori ◽  
Tomomi Saito ◽  
Yoshie Shiraga ◽  
...  

Glucose-dependent insulinotropic polypeptide (GIP) has been reported to have an atheroprotective property in animal models. However, the effect of GIP on macrophage foam cell formation, a crucial step of atherosclerosis, remains largely unknown. We investigated the effects of GIP on foam cell formation of, and CD36 expression in, macrophages extracted from GIP receptor-deficient (Gipr−/−) and Gipr+/+ mice and cultured human U937 macrophages by using an agonist for GIP receptor, [D-Ala2]GIP(1–42). Foam cell formation evaluated by esterification of free cholesterol to cholesteryl ester and CD36 gene expression in macrophages isolated from Gipr+/+ mice infused subcutaneously with [D-Ala2]GIP(1–42) were significantly suppressed compared with vehicle-treated mice, while these beneficial effects were not observed in macrophages isolated from Gipr−/− mice infused with [D-Ala2]GIP(1–42). When macrophages were isolated from Gipr+/+ and Gipr−/− mice, and then exposed to [D-Ala2]GIP(1–42), similar results were obtained. [D-Ala2]GIP(1–42) attenuated ox-LDL uptake of, and CD36 gene expression in, human U937 macrophages as well. Gene expression level of cyclin-dependent kinase 5 (Cdk5) was also suppressed by [D-Ala2]GIP(1–42) in U937 cells, which was corelated with that of CD36. A selective inhibitor of Cdk5, (R)-DRF053 mimicked the effects of [D-Ala2]GIP(1–42) in U937 cells. The present study suggests that GIP could inhibit foam cell formation of macrophages by suppressing the Cdk5-CD36 pathway via GIP receptor.


2021 ◽  
Vol 36 ◽  
pp. 153331752110128
Author(s):  
Hana Na ◽  
Hua Tian ◽  
Zhengrong Zhang ◽  
Qiang Li ◽  
Jack B. Yang ◽  
...  

Intraperitoneal injection of amylin or its analog reduces Alzheimer’s disease (AD) pathology in the brains. However, self-injecting amylin analogs is difficult for patients due to cognitive deficits. This work aims to study the effects of amylin on the brain could be achieved by oral delivery as some study reported that amylin receptor may be present in the gastrointestinal tract. A 6-week course of oral amylin treatment reduced components of AD pathology, including the levels of amyloid-β, phosphorylated tau, and ionized calcium binding adaptor molecule 1. The treatment reduced active forms of cyclin-dependent kinase 5. Oral amylin treatment led to improvements in social deficit in AD mouse. Using immunofluorescence, we observed the amylin receptor complexed with the calcitonin receptor and receptor activity-modifying proteins in the enteric neurons. The study suggests the potential of the oral delivery of amylin analogs for the treatment of AD and other neurodegenerative diseases through enteric neurons.


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