title: Comparative analysis of two C-terminal kinesin motor proteins: KIFC1 and KIFC5A.
abstract: We have taken advantage of the close structural relationship between two C-terminal motors, KIFC5A and KIFC1, to examine the sequence requirements for targeting of these two motors within the cell. Although KIFC5A and KIFC1 are almost identical in their motor and stalk domains, they differ in well-defined regions of their tail domains. Specific antisera to these motors were used to determine their localization to distinct subcellular compartments, the spindle for KIFC5A or membranous organelles for KIFC1. In addition to defining the intracellular localization of KIFC1, the reactivity of the KIFC1 antibody demonstrates that this motor contains a frame shift with respect to KIFC5A and is likely the product of a separate gene. The divergent tail domains of these motors are predicted to harbor specific information that directs them to their correct intracellular targets. In order to define the sequences responsible for the differential localization of these two motors, GFP was fused to motors with various tail deletions and their localization visualized after transfection. We were able to identify distinct sequences in each motor responsible for its unique cellular localization. The KIFC5A tail contains a 43 amino acid sequence with both nuclear localization and microtubule binding activity while KIFC1 contains a 19 amino acid sequence sufficient to target this motor to membrane-bounded organelles.
authors.affiliation: Department of Anatomy and Cell Biology, Brody School of Medicine at East Carolina University, Greenville, North Carolina, USA.
authors.forename: Yuguo
authors.initials: Y
authors.lastname: Zhang
authors.forename: Ann O
authors.initials: AO
authors.lastname: Sperry
mesh_terms: D016475:3T3 Cells; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D002467:Cell Nucleus / Q000737:chemistry / Q000378:metabolism; D051379:Mice; D008869:Microtubule-Associated Proteins / Q000737:chemistry* / Q000235:genetics; D008870:Microtubules / Q000378:metabolism; D008969:Molecular Sequence Data; D019913:Nuclear Localization Signals / Q000737:chemistry / Q000235:genetics; D009687:Nuclear Proteins / Q000737:chemistry* / Q000235:genetics; D017434:Protein Structure, Tertiary; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics; D020539:Sequence Analysis, Protein; D014162:Transfection; D028961:beta Karyopherins / Q000737:chemistry* / Q000235:genetics
chemical_list: C411575:KIFC5 protein, mouse; C496267:Kifc1 protein, mouse; D008869:Microtubule-Associated Proteins; D019913:Nuclear Localization Signals; D009687:Nuclear Proteins; D011993:Recombinant Fusion Proteins; D028961:beta Karyopherins