The activation of Src kinase in cells is strictly controlled by intramolecular inhibitory interactions mediated by SH3 and SH2 domains. They impose structural constraints on the kinase domain holding it in a catalytically non-permissive state. The transition between inactive and active conformation is known to be largely regulated by the phosphorylation state of key tyrosines 416 and 527. Here, we identified that phosphorylation of tyrosine 90 reduces binding affinity of the SH3 domain to its interacting partners, opens the Src structure, and renders Src catalytically active. This is accompanied by an increased affinity to the plasma membrane, decreased membrane motility, and slower diffusion from focal adhesions. Phosphorylation of tyrosine 90 controlling SH3-medited intramolecular inhibitory interaction, analogical to tyrosine 527 regulating SH2-C-terminus bond, enables SH3 and SH2 domains to serve as cooperative but independent regulatory elements. This mechanism allows Src to adopt several distinct conformations of varying catalytic activities and interacting properties, enabling it to operate not as a simple switch but as a tunable regulator functioning as a signalling hub in a variety of cellular processes.

• Klíčová slova
• SH3 domain, Src, biochemistry, cell biology, cell transformation, chemical biology, invasiveness, mouse, phosphorylation, protein structure,
• MeSH
• fosforylace MeSH
• skupina kinas odvozených od src-genu * metabolismus   MeSH
• src homologní domény * MeSH
• tyrosin metabolismus   MeSH
• tyrosinkinasy metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• skupina kinas odvozených od src-genu * MeSH
• tyrosin MeSH
• tyrosinkinasy MeSH

Interaction scaffolds that selectively recognize disordered protein strongly shape protein interactomes. An important scaffold of this type that contributes to transcription is the TFIIS N-terminal domain (TND). The TND is a five-helical bundle that has no known enzymatic activity, but instead selectively reads intrinsically disordered sequences of other proteins. Here, we review the structural and functional properties of TNDs and their cognate disordered ligands known as TND-interacting motifs (TIMs). TNDs or TIMs are found in prominent members of the transcription machinery, including TFIIS, super elongation complex, SWI/SNF, Mediator, IWS1, SPT6, PP1-PNUTS phosphatase, elongin, H3K36me3 readers, the transcription factor MYC, and others. We also review how the TND interactome contributes to the regulation of transcription. Because the TND is the most significantly enriched fold among transcription elongation regulators, TND- and TIM-driven interactions have widespread roles in the regulation of many transcriptional processes.

• Klíčová slova
• intrinsically disordered proteins, molecular scaffolds, structural biology, transcription,
• MeSH
• elongin metabolismus   MeSH
• regulace genové exprese MeSH
• transkripční elongační faktory * chemie   genetika   metabolismus   MeSH
• transkripční faktory * metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Research Support, N.I.H., Extramural MeSH
• Názvy látek
• elongin MeSH
• transcription factor S-II MeSH Prohlížeč
• transkripční elongační faktory * MeSH
• transkripční faktory * MeSH

Pathogenic Candida albicans yeasts frequently cause infections in hospitals. Antifungal drugs lose effectiveness due to other Candida species and resistance. New medications are thus required. Secreted aspartic protease of C. parapsilosis (Sapp1p) is a promising target. We have thus solved the crystal structures of Sapp1p complexed to four peptidomimetic inhibitors. Three potent inhibitors (Ki: 0.1, 0.4, 6.6 nM) resembled pepstatin A (Ki: 0.3 nM), a general aspartic protease inhibitor, in terms of their interactions with Sapp1p. However, the weaker inhibitor (Ki: 14.6 nM) formed fewer nonpolar contacts with Sapp1p, similarly to the smaller HIV protease inhibitor ritonavir (Ki: 1.9 µM), which, moreover, formed fewer H-bonds. The analyses have revealed the structural determinants of the subnanomolar inhibition of C. parapsilosis aspartic protease. Because of the high similarity between Saps from different Candida species, these results can further be used for the design of potent and specific Sap inhibitor-based antimycotic drugs.

• Klíčová slova
• Inhibitor, crystal structure, hydrogen bonds, noncovalent interactions, peptidomimetics,
• MeSH
• aspartátové endopeptidasy antagonisté a inhibitory   metabolismus   MeSH
• Candida parapsilosis enzymologie   MeSH
• fungální proteiny antagonisté a inhibitory   metabolismus   MeSH
• inhibitory proteas chemická syntéza   chemie   farmakologie   MeSH
• molekulární modely MeSH
• molekulární struktura MeSH
• peptidomimetika chemická syntéza   chemie   farmakologie   MeSH
• vztah mezi dávkou a účinkem léčiva MeSH
• vztahy mezi strukturou a aktivitou MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• aspartátové endopeptidasy MeSH
• fungální proteiny MeSH
• inhibitory proteas MeSH
• peptidomimetika MeSH
• SAPP1 protein, Candida parapsilosis MeSH Prohlížeč

Protein kinase N3 (PKN3) is a serine/threonine kinase implicated in tumor progression of multiple cancer types, however, its substrates and effector proteins still remain largely understudied. In the present work we aimed to identify novel PKN3 substrates in a phosphoproteomic screen using analog sensitive PKN3. Among the identified putative substrates we selected ARHGAP18, a protein from RhoGAP family, for validation of the screen and further study. We confirmed that PKN3 can phosphorylate ARHGAP18 in vitro and we also characterized the interaction of the two proteins, which is mediated via the N-terminal part of ARHGAP18. We present strong evidence that PKN3-ARHGAP18 interaction is increased upon ARHGAP18 phosphorylation and that the phosphorylation of ARHGAP18 by PKN3 enhances its GAP domain activity and contributes to negative regulation of active RhoA. Taken together, we identified new set of potential PKN3 substrates and revealed a new negative feedback regulatory mechanism of Rho signaling mediated by PKN3-induced ARHGAP18 activation.

• Klíčová slova
• ARHGAP18, PKN3, Rho-GTP, phosphoproteomic screen, phosphorylation,
• MeSH
• fosforylace MeSH
• lidé MeSH
• nádorové buněčné linie MeSH
• proteinkinasa C genetika   metabolismus   MeSH
• proteiny aktivující GTPasu metabolismus   MeSH
• proteomika metody   MeSH
• sekvence aminokyselin MeSH
• signální transdukce MeSH
• substrátová specifita MeSH
• vazba proteinů MeSH
• zpětná vazba fyziologická MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• ARHGAP18 protein, human MeSH Prohlížeč
• protein kinase N MeSH Prohlížeč
• proteinkinasa C MeSH
• proteiny aktivující GTPasu MeSH

Protein p130Cas constitutes an adaptor protein mainly involved in integrin signaling downstream of Src kinase. Owing to its modular structure, p130Cas acts as a general regulator of cancer cell growth and invasiveness induced by different oncogenes. However, other mechanisms of p130Cas signaling leading to malignant progression are poorly understood. Here, we show a novel interaction of p130Cas with Ser/Thr kinase PKN3, which is implicated in prostate and breast cancer growth downstream of phosphoinositide 3-kinase. This direct interaction is mediated by the p130Cas SH3 domain and the centrally located PKN3 polyproline sequence. PKN3 is the first identified Ser/Thr kinase to bind and phosphorylate p130Cas and to colocalize with p130Cas in cell structures that have a pro-invasive function. Moreover, the PKN3-p130Cas interaction is important for mouse embryonic fibroblast growth and invasiveness independent of Src transformation, indicating a mechanism distinct from that previously characterized for p130Cas. Together, our results suggest that the PKN3-p130Cas complex represents an attractive therapeutic target in late-stage malignancies.

• Klíčová slova
• CAS, BCAR1, PKN3, SH3, Src, p130Cas,
• MeSH
• fibroblasty metabolismus   MeSH
• fosforylace MeSH
• fosfothreonin metabolismus   MeSH
• invazivní růst nádoru MeSH
• kontraktilní svazky metabolismus   MeSH
• lidé MeSH
• myši nahé MeSH
• nádory metabolismus   patologie   MeSH
• podozomy metabolismus   MeSH
• pohyb buněk MeSH
• proliferace buněk MeSH
• proteinkinasa C metabolismus   MeSH
• pseudopodia metabolismus   MeSH
• skupina kinas odvozených od src-genu metabolismus   MeSH
• substrátový protein asociovaný s Crk metabolismus   MeSH
• vazba proteinů MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• fosfothreonin MeSH
• protein kinase N MeSH Prohlížeč
• proteinkinasa C MeSH
• skupina kinas odvozených od src-genu MeSH
• substrátový protein asociovaný s Crk MeSH