Welcome to the Huq Lab website
Research in the Huq lab is focused on understanding how plants sense, interpret and respond to environmental light conditions that regulate almost every aspect of the plant life cycle from seed germination to flowering time. Specifically, we focus on the red/far-red light photoreceptors (phytochromes) and their interacting factors to understand early signaling events. This approach has taken us in two directions: light-regulation of protein degradation and light-regulated pre-mRNA splicing in Arabidopsis. The protein degradation aspect is focused understanding the fundamental mechanisms of degradation of Phytochrome Interacting Factors (PIFs) in response to light. Phytochromes promote photomorphogenesis in response to red/far-red light, while PIFs repress photomorphosgenesis (promote skotomorphogenesis) in the dark. Therefore, they have a “Yin-Yang” relationship. Phytochromes undergo allosteric conformational changes from the biologically inactive form (Pr) to the active form (Pfr) in response to light. The photoactivated phytochromes translocate into the nucleus and physically interact with PIFs. The interaction between the Pfr-phys and PIFs triggers a rapid phosphorylation and poly-ubiquitylation followed by a very quick degradation of PIFs through the 26S proteasome pathway. The rapid removal of PIFs results in a cascade of gene expression changes that promote photomorphogenesis. These biochemical changes along with others allow plants to adjust their growth and development in response to environmental changes very rapidly. We made tremendous progress in understanding the pervasive roles of PIFs in regulating plant growth and development, and in identifying and characterizing the kinases, phosphatases and the E3 ubiquitin ligases necessary for fine-tuning PIF levels in plants. However, there are many aspects of these regulations that are still unknown. We are using a combination of biochemical, genetic, molecular and functional genomic approaches to understand (i) the mechanisms of light-induced degradation of PIFs, (ii) how phytochromes transduce light signals to their signaling partner PIFs, and (iii) combinatorial control of photomorphogenesis by the bHLH class of transcription factors.
For light-regulated pre-mRNA splicing, we have identified three splicing factors called SFPS, RRC1 and SWAP1 as interacting partners for phyB. We are trying to understand how these factors regulate pre-mRNA splicing in response to light and how phyB modulates their activities.
Our research is supported by the National Institute of Health (NIH), National Science Foundation (NSF), Human Frontier Science Program (HFSP) and US-Israel Binational Foundation (BSF).
