wildtype ptk2 line (ATCC)
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Wildtype Ptk2 Line, supplied by ATCC, used in various techniques. Bioz Stars score: 94/100, based on 181 PubMed citations. ZERO BIAS - scores, article reviews, protocol conditions and more
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Average 94 stars, based on 181 article reviews
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1) Product Images from "Mammalian metaphase kinetochores are elastic and require condensin for robust structure and function"
Article Title: Mammalian metaphase kinetochores are elastic and require condensin for robust structure and function
Journal: bioRxiv
doi: 10.64898/2025.12.23.696255
Figure Legend Snippet: (A) Schematic of kinetochore analysis framework. (B) Representative timelapse of PtK2 cell demonstrating a representative small-scale and large-scale deforming kinetochore, visualized by eGFP-CENP-A and Hec1-Halotag with JF549 dye, with intensity linescan along the force (K-K) axis and best Gaussian fits for boxed kinetochores. Red text denotes length measurement using full-width at half maximum of Gaussian fits. Blue text denotes length measurement using AUC/peak calculation. White lines are drawn to approximate spindle shape and k-fibers. (C) Mean length of individual kinetochores over their imaging lifetime for eGFP-CENP-A and Hec1-Halotag with JF549 dye (m = 14 cells, n = 122 kinetochores; mean ± SD; Mann-Whitney test), with control 200 nm beads (in 488 and 561 nm imaging wavelengths) analyzed with the same method (n = 22). (D) Correlation between CENP-A length and Hec1 length over each timepoint. Dotted black line indicates a 1:1 comparison and red line indicates the best fit (m = 14 cells, n = 6502 timepoints; Simple linear regression). (E) Standard deviation of length of the same individual kinetochores and 200 nm beads as in (C). (F) Model cartoon depicting the sliding of parallel linkages that occur to allow for the scale of shape changes observed for CENP-A and Hec1.
Techniques Used: Imaging, MANN-WHITNEY, Control, Comparison, Standard Deviation
Figure Legend Snippet: (A) Schematic of how kinetochore shape changes occur with merotelic attachments. (B) Representative timelapses of a PtK2 kinetochore pair (eGFP-CENP-A and Hec1-Halotag with JF549 dye) in a control cell, Hec1–9A-HaloTag overexpression cell, and 3 μM ZM447439 (ZM) treated cell, with right kinetochore displayed as stationary (grey line). (C) Mean (from left to right columns: 435 ± 60 nm, 442 ± 83 nm, 467 ± 81 nm, 461 ± 67 nm, 482 ± 92 nm, and 494 ± 96 nm) and (D) standard deviation (from left to right columns: 39 ± 17 nm, 46 ± 22 nm, 52 ± 24 nm, 44 ± 22 nm, 50 ± 28 nm, 59 ± 37 nm) of individual kinetochores imaging lifetime for eGFP-CENP-A and Hec1-Halotag with JF549 dye control (m = 14 cells, n = 122 kinetochores), Hec1–9A-Halotag (+JF549 dye) transient expression (m = 6 cells, n = 79 kinetochores), and ZM treatment (m = 16 cells, n = 86 kinetochores) (mean ± SD; Mann-Whitney test). (E) Cartoon of how kinetochore asymmetry is detected, visualized by CENP-A and Hec1 colocalized (white) with approximated k-fiber microtubules (grey lines, left) and DNA (grey area, right). Cartoon (below) depicts “tail” on the right side of the kinetochore. From the example intensity linescan, asymmetry is detected if the area under the curve (AUC) calculated for left and right side of the peak is greater than opposite side. For tail detection, the first derivative of the intensity curve is calculated. A tail is deemed present if there are >2 minima or maxima. (F) Percentage of total timepoints with Hec1 asymmetry detected for control, Hec1–9A expression, and ZM treatment. Significance from Chi-square test. (G) Percentage of total timepoints with Hec1 “tails” detected for control (371/6502 timepoints), Hec1–9A expression (280/3131 timepoints), and ZM treatment (929/4762 timepoints). Significance from Chi-square test. (H) Percentage of individual kinetochore’s lifetime with Hec1 “tails” detected for kinetochores in (C) and (D) (mean ± SEM; Mann-Whitney test). (I) Percentage of tails pointing to microtubule or DNA side for control (n = 222/371 tails towards DNA), Hec1–9A (89/280 tails towards DNA), and ZM-treated (558/929 tails towards DNA) kinetochores, for all individual timepoints with tails.
Techniques Used: Control, Over Expression, Standard Deviation, Imaging, Expressing, MANN-WHITNEY
Figure Legend Snippet: (A) Schematic of how kinetochore length changes occur with tension. (B) All (black line; m = 122 kinetochores; timepoints per increasing K-K bin n = 1420, 2623, 1518, 617), large-range (grey continuous line; m = 48 kinetochores; per K-K bin n = 522, 1054, 580, 246), and small-range (grey dashed line; m = 74 kinetochores; per K-K bin n = 898, 1569, 938, 371) kinetochores’ Hec1 lengths binned by K-K distance (tension), with bins with < 100 timepoints excluded. Large-range kinetochores were assigned by range of Hec1 lengths over each kinetochore’s imaging lifetime > mean range of all kinetochores. Small-range kinetochores have length ranges < mean range of all kinetochores (mean ± SEM; Mann-Whitney test done for first and last K-K distance bins). (C) Percent of K-K distance and CENP-A length increase per kinetochore during imaging lifetime; 74 ± 42% and 5 ± 10% (mean ± SD; Paired t-test). (D) Cartoon depicting assay to exert controlled force (10 μm over 18 s) on a k-fiber and its attached kinetochore with a glass microneedle, without membrane rupture ( ; ). (E) Potential outcomes of microneedle pulling before force, with high force, and after force: attached kinetochore deforms then relaxes (elastic response) or deforms and does not relax (plastic response). (F) Representative PtK2 cell timelapse of eGFP-CENP-A deforming with the microneedle pulling, and relaxing. The yellow arrowhead denotes the “front” sister kinetochore and the long yellow arrow indicates pulling. (G) K-K distance over time before, during, and after microneedle pulling for 6 kinetochores. “Initial” length is the frame before pulling begins. Time = 0 s corresponds to the time maximum K-K distance was measured during pulling. The grey box indicates the 18 s pulling period. (H) eGFP-CENP-A lengths over time before, during, and after microneedle pulling for 6 kinetochores as defined in (G). The grey box indicates the pulling period, during which kinetochore lengths were not measured due to motion blur. (I) CENP-A length before microneedle pulling (~5 s before), at the maximum K-K distance during pulling, and 30 s after pulling. N = 6 kinetochores (paired t-test). (J) Correlation of CENP-A length and K-K distance during the relaxation period after pulling (n = 6 kinetochores). R 2 = 0.74, significantly non-zero using simple linear regression. (K) Correlation of “back” (needle distal) kinetochore CENP-A length (black dots) and K-K distance during the relaxation period after pulling overlaid on “front” (needle proximal) kinetochore lengths (grey dots) as in (I). R 2 = 0.05 for “back” kinetochores, not significant from zero using simple linear regression. (L) Length fold change (strain) of CENP-A and K-K distance (92 ± 33%) and CENP-A (63 ± 56%) from before pulling and at maximum measured K-K distance (n = 6 kinetochores; Paired t-test).
Techniques Used: Imaging, MANN-WHITNEY, Membrane
Figure Legend Snippet: (A) Cartoon depicting loss of condensin I/II expecting to lead to more compliant chromatin. (B) Relative expression of SMC2 from control (siLuciferase) and siSMC2 cells from qPCR, normalized using actin and GAPDH as housekeeping genes. (C) Mean K-K distance per kinetochore pair for PtK2 control (m = 14 cells, n = 122 kinetochores) and SMC2 RNAi cells (m = 10 cells, n = 78 kinetochores) (mean ± SD; unpaired t-test). (D) Mean (from left to right: 435 ± 60 nm, 512 ± 70 nm, 461 ± 67 nm, 554 ± 81 nm) and (E) standard deviation (from left to right: 39 ± 17 nm, 73 ± 39 nm, 44 ± 22, 84 ± 42 nm) of length per kinetochore (eGFP-CENP-A and Hec1-Halotag with JF549 dye) over the imaging lifetime for control (n = 122 kinetochores) and siSMC2 cells (n = 78 kinetochores) (mean ± SD; Mann-Whitney test). (F) Percent of K-K distance and CENP-A length increase per kinetochore during imaging lifetime for control (n = 122; 74 ± 42% and 5 ± 10%) and siSMC2 cells (n = 78; 63 ± 35% and 4 ± 18%) (mean ± SD; Mann-Whitney test). (G) Percentage of timepoints of all imaged kinetochores displaying Hec1 “tails” for control (n = 6502 timepoints) and siSMC2 (n = 4075 timepoints) cells (Chi-square test). (H) Examples of Hec1 and CENP-A distributions with 1, 2, and 3 peaks with corresponding peak heatmap (multicolor images) and detection (white cross). (I) Percentage of timepoints of all imaged CENP-A kinetochores with 1, 2, or ≥3 peaks for control (n = 6502 total timepoints) and siSMC2 (n = 4075 total timepoints) cells (bottom) (Chi-square test). (J) Percentage of kinetochores for control (n = 122 kinetochores) and siSMC2 (n = 78 kinetochores) with >1 peak (31% for control and 76% for siSMC2) and with only 1 peak (69% for control and 24% for siSMC2) during its imaging lifetime (Chi-square test). (K) Percentage of each individual kinetochore’s imaging lifetime with >1 peak in Hec1 for control (n = 122 kinetochores) and siSMC2 (n = 78 kinetochores) cells (median; Mann-Whitney test).
Techniques Used: Expressing, Control, Standard Deviation, Imaging, MANN-WHITNEY
Figure Legend Snippet: (A) Representative PtK2 SMC2 RNAi cell timelapse of eGFP-CENP-A deforming with the microneedle pulling, and relaxing. Yellow box shows the zoomed in pair on the right, cyan arrow shows direction of needle movement, white arrowheads highlight the “front” kinetochore, and grey arrowheads highlight the “back” kinetochore. (B) K-K distance over time before, during, and after microneedle pulling for n = 9 kinetochores. “Initial” length is the frame just before pulling begins. Time = 0 s corresponds to the time maximum K-K distance was reached and measured during pulling, highlighting relaxation dynamics of each pulled kinetochore. The grey box indicates the pulling period. (C) CENP-A lengths over time before, during, and after microneedle pulling for 9 kinetochores as defined in (B). (D) CENP-A length at the frame before microneedle pulling, at the maximum K-K distance during pulling, and 30 s after pulling in siSMC2 cells (n = 9 kinetochores; Paired t-test). (E) Percent of K-K distance and CENP-A length increase from the frame before pulling begins to maximum measured K-K distance (n = 9 kinetochores; Paired t-test). (F) eGFP-CENP-A images at maximum measured K-K distance and 30s afterwards of control deformation and two siSMC2 kinetochore deformations exhibiting dramatic “tails”. (G) Percentage of control (n = 6) and siSMC2 (n = 9) kinetochore pulls with persistent “tails” for > 30 s during the relaxation period. (H) Timelapse comparing representative K-K distance relaxation for a control pull and for a fast relaxation SMC2 RNAi pull during the needle hold. White box indicates zoomed in pair. Grey dashed lines project the kinetochores’ movements over time. (I) Examples of non-detached (15 s after maximum K-K) and detached kinetochore (10 s after maximum K-K) from siSMC2 pulling experiments with fast K-K relaxation rates. Inset is of the front kinetochore with a linescan for tubulin intensity and kinetochore intensity; corresponding plots on the right annotated with sections of intensity signal corresponding to k-fiber presence or not. (J) K-K distance change after maximum K-K distance (t = 0) for control (black, n = 6 kinetochores), and detached, siSMC2 kinetochores (red and brown line, n = 2/9 kinetochores) pulls. (K) Percentage of pulls that led to detachment events in control and siSMC2 cells based on two criteria: fast K-K distance relaxation as in (J) and loss of tubulin signal attached to the kinetochore as in (I).
Techniques Used: Control