Regulated Targeting of a Protein Kinase into a Flagellum: Understanding Molecular Addresses for Proteins

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Biochemistry, Biophysics, and Structural Biology | Life Sciences


Michael Reagan, Biochemistry


Chlamydomonas reinhardtii is a biflagellate, unicellular alga that is used as a model organism to study photosynthesis, flagellar function, and fertilization. Previously, it was found that during the mating reaction of Chlamydomonas a 78 kDa form of the protein named CALK (Chlamydomonas aurora/Ipl1p-like protein kinase) moves from the cell body to the flagellum during gamete activation in this organism. The goal of this research was to study the domains of CALK responsible for its translocation from the cell body to the flagellum of Chlamydomonas. To this end, two constructs were cloned encoding CALK and an N-terminal tag – either HSV or GFP (green fluorescent protein). From these constructs, the plan was to create deletion constructs that would then be expressed in Chlamydomonas and studied to see their effect on CALK translocation. However, expression of the two CALK constructs was not possible. Some possible reasons for this expression difficulty include the lack of introns in the CALK construct, unsuitable or uninduced promoter systems, and the possibility that N-terminal tagging might disrupt the aurora kinase function on CALK eliminating the cell’s ability to undergo mitosis.