Browsing by Author "Jamsheer, K Muhammed"

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Evolution of TOR-SnRK dynamics in green plants and its integration with phytohormone signaling networks
(Oxford University Press, 2019) Jamsheer, K Muhammed; Jindal, Sunita; Laxmi, Ashverya
The Target Of Rapamycin-SNF1-Related Protein Kinase 1 (TOR-SnRK1) arms race is an ancient regulatory mechanism evolved in eukaryotes to regulate nutrient-dependent growth. The autotrophic nature makes plants a distinct class in the eukaryotic lineage. Although TOR-SnRK1 signaling cascade shows highly conserved functions, studies in the past two decades identified many important plant-specific innovations in this pathway. Plants also possess SnRK2 and SnRK3 kinases which are originated from the ancient SnRK1-related kinases and do specialized functions in controlling growth, stress responses and nutrient homeostasis in plants. Recently, an integrative picture has started to emerge where different SnRKs and TOR kinase are highly interconnected to control nutrient and stress responses of plants. Further, these kinases are intimately involved with phytohormone signaling networks which originated at different stages of plant evolution. In this review, we are highlighting the evolution and divergence of TOR-SnRKs signaling components in plants and their communication between each other and phytohormone signaling to fine-tune growth and stress responses in plants.
The FCS-LIKE ZINC FINGER 6 and 10 are involved in regulating osmotic stress responses in Arabidopsis
(Taylor & Francis Group, 2019) Jamsheer, K Muhammed; Singh, Dhriti; Sharma, Mohan; Sharma, Manvi; Jindal, Sunita; Mannully, Chanchal T.; Shukla, Brihaspati N.; Laxmi, Ashverya
The TARGET OF RAPAMYCIN-SNF1-RELATED PROTEIN KINASE 1 (TOR-SnRK1) arms race is a key regulator of plant growth in response to energy fluctuations and stress. Recently, we have identified that two members of the FCS-LIKE ZINC FINGER (FLZ) protein family, FLZ6 and 10, repress SnRK1 signaling and thereby involved in the activation of the TARGET OF RAPAMYCIN (TOR) signaling. In this study, we demonstrate that FLZ6 and 10 are also involved in the regulation of osmotic stress responses. Downregulation of FLZ6 and 10 results in enhanced expression of stress-responsive genes and better resilience towards osmotic stress at the seedling stage. These results indicate that FLZ6 and 10 are involved in the regulation of stress mitigation in plants through directly affecting SnRK1 signaling.
The FCS-like zinc finger scaffold of the kinase SnRK1 is formed by the coordinated actions of the FLZ domain and intrinsically disordered regions
(The American Society for Biochemistry and Molecular Biology, 2018) Jamsheer, K Muhammed; Shukla, Brihaspati N.; Jindal, Sunita; Gopan, Nandu; Mannully, Chanchal Thomas; Laxmi, Ashverya
The SNF1-related protein kinase 1 (SnRK1) is a heterotrimeric eukaryotic kinase that interacts with diverse proteins and regulates their activity in response to starvation and stress signals. Recently, the FCS-like zinc finger (FLZ) proteins were identified as a potential scaffold for SnRK1 in plants. However, the evolutionary and mechanistic aspect of this complex formation is currently unknown. Here, in silico analyses predicted that FLZ proteins possess conserved intrinsically disordered regions (IDRs) with a propensity for protein binding in the N and C termini across the plant lineage. We observed that the Arabidopsis FLZ proteins promiscuously interact with SnRK1 subunits, which formed different isoenzyme complexes. The FLZ domain was essential for mediating the interaction with SnRK1α subunits, whereas the IDRs in the N termini facilitated interactions with the β and βγ subunits of SnRK1. Furthermore, the IDRs in the N termini were important for mediating dimerization of different FLZ proteins. Of note, the interaction of FLZ with SnRK1 was confined to cytoplasmic foci, which colocalized with the endoplasmic reticulum. An evolutionary analysis revealed that in general, the IDR-rich regions are under more relaxed selection than the FLZ domain. In summary, the findings in our study reveal the structural details, origin, and evolution of a land plant–specific scaffold of SnRK1 formed by the coordinated actions of IDRs and structured regions in the FLZ proteins. We propose that the FLZ protein complex might be involved in providing flexibility, thus enhancing the binding repertoire of the SnRK1 hub in land plants.
Genome-wide identification and expression, protein-protein interaction and evolutionary analysis of the seed plant-specific BIG GRAIN and BIG GRAIN LIKE gene family
(Frontiers Media S.A., 2017) Mishra, Bhuwaneshwar S.; Jamsheer, K Muhammed; Singh, Dhriti; Sharma, Manvi; Laxmi, Ashverya
BIG GRAIN1 (BG1) is an auxin-regulated gene which functions in auxin pathway and positively regulates biomass, grain size and yield in rice. However, the evolutionary origin and divergence of these genes are still unknown. In this study, we found that BG genes are probably originated in seed plants. We also identified that seed plants evolved a class of BIG GRAIN LIKE (BGL) genes which share conserved middle and C-terminal motifs with BG. The BG genes were present in all monocot and eudicot species analyzed; however, the BGL genes were absent in few monocot lineages. Both BG and BGL were found to be serine-rich proteins; however, differences in expansion and rates of retention after whole genome duplication events were observed. Promoters of BG and BGL genes were found to be enriched with auxin-responsive elements and the Arabidopsis thaliana BG and BGL genes were found to be auxin-regulated. The auxin-induced expression of AthBG2 was found to be dependent on the conserved ARF17/19 module. Protein-protein interaction analysis identified that AthBG2 interact with regulators of splicing, transcription and chromatin remodeling. Taken together, this study provides interesting insights about BG and BGL genes and incentivizes future work in this gene family which has the potential to be used for crop manipulation.