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Fig. 7 | Molecular Brain

Fig. 7

From: Multiple myosin motors interact with sodium/potassium-ATPase alpha 1 subunits

Fig. 7

Interaction of actin-binding-site-less (ΔABS) and tail-less (Δtail) NMHC-IIs with Na+/K+-ATPase α1 subunits expressed in HEK293 cells. a Tail-less NMHC-IIs were made by deleting the tail regions, yellow shaded, of human (h) myh9 (i.e., hMyh9 AAs: 1928–1960), human (h) myh10 isoform 2 (i.e., hMyh10.2 AAs: 1934–1976) and mouse (m) myh14 isoform 3 (i.e., mMyh14.3 AAs:1946–1992) following a conserved proline residue (bold and underlined) where the numbers indicate the position of the amino acids in the WT constructs. b Actin-binding-site-less (ΔABS) NMHC-IIs were made by deleting a 23 amino acids (AAs) segment, yellow shaded, of hMyh9 (i.e., AAs: 654–676), hMyh10.2 (i.e., AAs: 661–683) and mMyh14.3 (i.e., AAs: 674–696). For both (a) and (b) symbols below sequences indicate fully (*), strongly (:) or weakly (.) conserved residues, and the lack of a symbol indicates amino acid divergence. c The actin binding site (ABS) of human myh14. The 3-D coordinates of human myh14 was retrieved from protein data bank (PDB: 5I4E). Structural features of myh14 was visualized and analyzed using UCSF Chimera (http://www.cgl.ucsf.edu/chimera/). Left panel shows the relative position of the ABS (red ribbon), nucleotide analog (adenosine diphosphate vanadate (ADP.VO4): ball and stick model) binding site and N-terminal SH3 domain (deep blue) in the motor domain of human myh14 (5I4E.pdb). The center and right panel show the relative position of the ABS (red ribbon; and ball and stick model) with respect to the position of the adenosine diphosphate vanadate (ADP.VO4) and magnesium co-factor (green ball) in the motor domain of myh14. d Tail-less (Δtail) but not actin-binding-site-less (ΔABS) myh14 co-immunoprecipitate Na+/K+-ATPase α1 subunits expressed in HEK293 cells. Lysates of non-transfected HEK293 cells (In; 1) or HEK293 cells transiently transfected with GFP (In; 4), myh14-GFP (In; 7), myh14-ΔABS-GFP (In; 10), or myh14-Δtail-GFP (In; 13) plasmids (where the GFP tag is in their C-terminus) were precleared with rabbit IgG (PC; lanes 2, 5, 8, 11 and 14) prior to immunoprecipitation using rabbit anti-GFP antibodies (IP; lanes 3, 6, 9, 12 and 15). Loading of PC complexes in the gel preceded those of the IP complexes. Presence of Na+/K+-ATPase α1 immunoreactive bands in lanes 1, 4, 7, 9, 10, 13 and 15 and absence of any Na+/K+-ATPase α1 immunoreactive bands in lanes 2, 3, 5, 6, 8, 11, 12 and 14 (in (i)) indicated co-immunoprecipitation of Na+/K+-ATPase α1 subunits from HEK293 cells transfected with myh14-GFP or myh14-Δtail-GFP plasmids but not from non-transfected HEK293 cells or those transfected with GFP or myh14-ΔABS-GFP plasmids. While myh14-ΔABS-GFP showed almost complete loss of actin binding (indicated with double asterisk ‘*’; lane 12, panel (ii)) both myh14-GFP and myh14-Δtail-GFP co-immunoprecipitated β-actin (lane 9 and lane 15 in panel (ii) respectively). Full length images of western blots are presented in Additional file 7: Figure S6 B

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