In our lab we study signalling mechanisms in the nervous system that regulate assembly of synapses, their function, and systemic communication during organ growth and maturation. We are particularly interested in the regulation of these physiological processes by the Mon1-CCZ1 (MC1) complex that regulates cellular trafficking along the endo-lysosomal pathway- a pathway that is impaired in neurodegenerative diseases such as Charcot-Marie-Tooth 2B.

The Drosophila larval neuromuscular junction (nmj) is a well-established model for studying synaptic development and function. Similar to mammalian central nervous system, these synapses are glutamatergic.  Studies have shown that post-synaptic glutamate receptors play a key role synaptic homeostasis. A decrease in receptor levels triggers a retrograde signal (muscle to nerve) that eventually leads to compensatory increase in neurotransmitter release thus maintaining homeostasis.

In our lab, we have identified Mon1 as a transsynaptic factor that negatively regulates glutamate receptor levels in an anterograde manner at the nmj. In addition, Mon1 also functions as an important molecular component of a neural circuit that controls gonad maturation through regulation of insulin-like peptides. Our current investigations are aimed at understanding how modulation of endo-lysosomal trafficking events regulates these physiological events.

Another area of study in the lab involves identifying mechanisms that regulate glial morphology and its implication to neuronal function. Of particular interest is the GPCR signalling pathway activated by the ligand Folded gastrulation (Fog). On-going studies are aimed at identifying cell-autonomous and cell non-autonomous factors that modulate this pathway to regulate glial morphogenesis.

Publications:

1. Lakshmi Bugga, Anuradha Ratnaparkhi, and Kai Zinn (2009).  The cell surface receptor Tartan is a potential in vivo substrate for the receptor tyrosine phosphatase Ptp52F. Mol Cell Biol. 29(12):3390-400.
2. Ratnaparkhi A. (2013) Signaling by Folded gastrulation is modulated by mitochondrial fusion and fission. J Cell Sci. 1;126:5369-76.
3. Deivasigamani S, Verma HK, Ueda R, Ratnaparkhi A, Ratnaparkhi GS. .(2014). A genetic screen identifies Tor as an interactor of VAPB in a Drosophila model of amyotrophic lateral sclerosis. Biol Open. 3(11):1127-38
4. Deivasigamani S, Basargekar A, Shweta K, Sonavane P, Ratnaparkhi GS, Ratnaparkhi A (2015).A Presynaptic Regulatory System Acts Transsynaptically via Mon1 to Regulate Glutamate Receptor Levels in Drosophila. Genetics. 2015 Oct;201(2):651-64.
5. Dhiman N, Shweta K, Tendulkar S, Deshpande G, Ratnaparkhi GS, Ratnaparkhi A (2019) Drosophila Mon1 constitutes a novel node in the brain-gonad axis that is essential for female germline maturation. Development, 146(13):dev166504.
6. Rohit H KrishnanA, Shweta Tendulkar, Senthilkumar Deivasigamani , Anuradha Ratnaparkhi, Girish S Ratnaparkhi (2019). Monensin sensitive 1 regulates dendritic arborization in Drosophila by modulating endocytic flux. Frontiers in Cell and Developmental Biology, 2;7:145.
7. Anagha Basargekar, Shweta Yogi, Zeeshan Mushtaq, Senthilkumar Deivasigamani, Vimlesh Kumar,      Girish Ratnaparkhi, Anuradha Ratnaparkhi (2020). Drosophila Mon1 and Rab7 interact to regulate glutamate receptor levels at the neuromuscular junction. Int. J.Dev.Biol, 64(4-5-6):289-297.
8. Kumari Shweta, Anagha Basargekar and Anuradha Ratnaparkhi (2021) FGFR/Heartless and Smog interact synergistically to negatively regulate Fog mediated G-protein coupled receptor signaling in the Drosophila nervous system. G3 (Bethesda), 11(3), jkaa029.
9. Tendulkar S, Hegde S, Garg L, Thulasidharan A, Kaduskar B, Ratnaparkhi A, Ratnaparkhi GS (2022).  Caspar, an adapter for VAPB and TER94, modulates the progression of ALS8 by regulating IMD/NFκB-mediated glial inflammation in a Drosophila model of human disease. Hum Mol Genet. 231(17):2857-2875
10. Ratnaparkhi A, Sudhakaran J (2022).  Neural pathways in nutrient sensing and insulin signalling. Front Physiol.13:1002183
11. Rai P, Ratnaparkhi A, Kumar Roy J (2023).  Rab11 rescues muscle degeneration and synaptic morphology in the park13/+ Parkinson model of Drosophila melanogaster. Brain Res. 1816:148442.

Book Chapter/Book Review

1. Kriti Chaplot, Anuradha Ratnaparkhi, Girish Ratnaparkhi (2019). ‘Understanding motor disorders using flies’in M. Mutsuddi and A. Mukherjee (Eds), ‘Insights into Human neurodegeneration: Lessons learnt from Drosophila’, 131-162 (Springer).
2. Anuradha Ratnaparkhi (2020). ‘Introduction to the embryonic nervous system in Drosophila’ in S.C.Lakhotia and H.A. Ranganath (Eds), ‘ Experiments with Drosophila for Biology Courses’, India Academy of Sciences, Bengaluru.
3. Ratnaparkhi, A (2021) ‘Code of Life: Revolutions in Genetics’,  Mohan Sundara Rajan. Current Science, 120: 1256.