[R35] Molecular Mechanisms of Non-muscle Myosin II Contractility
Ente: National Institute of General Medical Sciences
Scadenza: 2031-02-28
Importo max: 430.383 EUR
Paese: US
Descrizione
PROJECT SUMMARY/ABSTRACT
Non-muscle myosin II (NMII) contractility is critical to number cellular processes from development to disease.
NMII is an ATP-dependent molecular motor that functions as a dimer composed of two heavy chains, which are
made of an ATPase/motor domain that binds actin and a coiled-coil tail domain. It is also bound to two
accessory proteins, the essential light chain which plays structural roles, and the regulatory light chain which is
the target of phosphorylation, integrating the molecule into a myriad of signaling pathways. Phosphorylation of
the regulatory light chain leads to a relief of an autoinhibition, opening up the molecule and making it
competent to bind actin, however, by itself it is a poor motor protein. The second required step of activation is
oligomerization into higher ordered, bi-polar filaments. This oligomerization is thought to be regulated by the
tail domain where again, phosphorylation is hypothesized to be the main driver of this transition. While
decades of research have revealed much about these biochemical and biophysical properties, we questioned
whether there were other, yet-to-be revealed, mechanisms that may contribute to NMII’s regulation. The
overarching goal of this proposal is to understand the mechanisms that regulate NMII contractility. In Project 1,
we explore a potential novel NMII binding protein, Split Discs (Spdi). Spdi’s human homolog, SPECC11L has
been implicated in a spectrum of cranial-facial pathologies, highly suggestive of abearent cranial neural crest
cell migration. SPECC1L was initially characterized as actin-microtubule crosslinking proteins, however data
from my lab suggests that its target is NMII and actin. It is our hypothesis that Spdi binds NMII to regulate its
contractility. Through a series of biochemical characterization and cell biology experiments where we elucidate
the mechanism by which Spdi associates with NMII, and employ an ex-vivo developmental model to
understand how its regulation of contractility affects collective cell migration. In Project 2 we focus on the role
of acetylation on the regulation of NMII filament assembly. While phosphorylation has long been thought of as
the major driver of NMII dynamics and behavior, recent data from my lab suggests that acetylation may play an
equally important role in this process. We will identify the enzymes involved in this acetylation-deacetylation
cycle, and elucidate the role this post-translational modification has on force generation. The proposed
research spans the molecular and biochemical, to cell biology and development, integrating high-resolution
microscopy and capitalizing on Drosophila and the broad genetic tools they provide. Given the high degree of
conservation and its universality to number of critical cellular processes the results we obtain here will have
broad implications for how NMII is regulated across species and will bring new insights to how NMII is
integrated in cellular signaling pa
Istituzione: REED COLLEGE
PI: Derek Anthony Applewhite
Progetto: 1R35GM164067-01
Settori: National Institute of General Medical Sciences
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