Studies of Alpha Kinase 1 and its potential to influence cytoskeletal reorganization

UNCG Author/Contributor (non-UNCG co-authors, if there are any, appear on document)
Kyle D. Burgett (Creator)
The University of North Carolina at Greensboro (UNCG )
Web Site:
Paul Steimle

Abstract: Maintaining and remodeling the actin cytoskeleton is a critical part of normal cellular functioning for all eukaryotes, as it is crucial for cell movement, endocytosis, exocytosis, and maintaining cellular morphology. Within the social amoeba Dictyostelium discoideum, myosin II associates with the actin cytoskeleton and is directly responsible for the contraction of opposing actin filaments. Cytoskeletal remodeling is achieved by cycling myosin II between a bipolar filamentous form and a monomeric form. In Dictyostelium, the family of alpha kinases known as myosin heavy chain kinases (MHCKs) has been shown to be the primary regulators of myosin II bipolar filament turnover. By phosphorylating specific threonine residues on the tail region of the myosin II protein, MHCKs control the assembly/disassembly of myosin II filaments. Alpha Kinase 1 (AK1) represents a previously uncharacterized member of the MHCK family in Dictyostelium. The data presented in this thesis provides evidence that AK1 can influence myosin II bipolar filament turnover and indeed act as a myosin II heavy chain kinase. Overexpression of AK1 yields a myosin II null phenotype, characterized by cytoskeletal defects arising from elevated levels of phosphorylated monomeric myosin II, as evidenced by 1) an inability to complete cytokinesis in suspension culture, and 2) delayed multicellular development. Localization studies performed with GFP-tagged AK1 reveal a localization pattern that is consistent with a role for AK1 in vesicle trafficking, unique amongst the MHCKs. Taken together, these data support the hypothesis that AK1 can function as a MHCK in Dictyostelium and suggest that more detailed biochemical and cellular studies of AK1 are warranted to fully characterize this unique protein and its potential role in regulating myosin II activity.

Additional Information

Language: English
Date: 2016
Actin, Chemotaxis, Cytoskeleton, Dictyostelium, MHCK, Myosin II
Dictyostelium discoideum

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