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Maitreyi Das @daslabpombe.com · 16/09/2026

The Das lab has 1-2 open postdoctoral positions. Our lab investigates the fundamentals of cell-cycle-dependent cell polarity. Boston College has fantastic resources, including a cutting-edge imaging facility with state-of-the-art microscopes. Please apply here: bc.csod.com/ux/ats/caree...

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Maitreyi Das @daslabpombe.com · 02/09/2026

Last call! ⏰ September 14 is the FINAL deadline to submit a talk or poster abstract for #CellBio2026, #ASCB Share your science with the cell biology community. 🔬 www.ascb.org/cellbio2026/...

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Maitreyi Das @daslabpombe.com · 27/06/2026

Day 10. Good bye Rome. Heading home after the most meaningful experience of life. This is a gift I will hold and cherish forever. I made some really good friends along the way. The places we visited were magical, the food exquisite but it really was the compania that made this trip such a success.

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Maitreyi Das @daslabpombe.com · 25/06/2026

Day 9. Started the day with Mass in the basilica of st. Peter and then had the whole day free to ourselves. Enjoyed a bus tour of the city. Its toooooo hot to walk.

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Maitreyi Das @daslabpombe.com · 24/06/2026

Day 8. We got to listen to the president of the Gregorian University, Fr. Mark Lewis, audience with the pope, saw the tomb of st. Peter in the vatican and visited the church of Gesu.

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Maitreyi Das @daslabpombe.com · 23/06/2026

Day 7. Good bye Barcelona, hello Rome.

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Maitreyi Das @daslabpombe.com · 22/06/2026

Day 6. In Barcelona. Visited the Basilica Santa Maria del Mar and La Sagrada Famalia. The later was the most moving experience I have had in this trip so far.

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Maitreyi Das @daslabpombe.com · 21/06/2026

You are welcome. Montserrat was outstanding. We took the cable car. I suggest visiting in time for the vespers. They choir is very good and it is a special experience. We stayed the night at the monastery.

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Maitreyi Das @daslabpombe.com · 21/06/2026

Day 5 at Manresa. Visited the cave where st. Ignatius wrote his spiritual exercises, and visited a basilica where he prayed. Also got to enjoy black rice for lunch. So so good.

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Maitreyi Das @daslabpombe.com · 20/06/2026

This 10 day journey follows the journey of st. Ignatius. We started in Burgos>Bilbao>Loyola>Zaragoza.......I am on day 4

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Maitreyi Das @daslabpombe.com · 20/06/2026

I got the most amazing gift this summer. I was invited to join the Campania-Ignatian pilgrimage with some wonderful colleagues from @bostoncollege.bsky.social . This has been one of my best experiences. I am currently in Sos del Rey Catolico, Zaragoza in Spain.

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Maitreyi Das @daslabpombe.com · 15/02/2026

Our finding indicates that in interphase cells, septins along the cortex prevent Rga4 mobility and localization to the cell ends. When cells enter mitosis, septins are lost from the cell sides, and Rga4 is mobile and does not accumulate to form punctae. 12/

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Maitreyi Das @daslabpombe.com · 15/02/2026

Correspondingly, in its3-1 mutant, we observe enhanced Rga4 punctae. This indicates that the septin cytoskeleton limits Its3-dependent PIP2 levels to promote immobile Rga4 puncta. Increased PIP2 levels as seen in septin mutants promote Rga4 mobility and loss of punctae. 11/

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Maitreyi Das @daslabpombe.com · 15/02/2026

We asked if the presence of septins somehow maintained proper conditions for immobile punctate Rga4 localization. Since Rga4 is membrane bound, we looked at lipid orgnization in septin mutants. we find enhanced PIP2 and its kinase Its3 at the cortex in spn1 mutants, while a decrease in PIP. 10/

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Maitreyi Das @daslabpombe.com · 15/02/2026

Next, we asked whether the septin physically interacts with Rga4 to regulate its localization. We do not see any evidence of Septin-Rga4 interaction. However, when we mis-localize septins to the mitochondria with a GBP-Tom20 trap, Rga4 at the cortex is diffuse similar to that in septin mutants. 9/

Spn3-GFP localized to the mitochondria, and Rga4-mCherry appears diffuse along the cortex.

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Maitreyi Das @daslabpombe.com · 15/02/2026

When cells enter mitosis, the cortical septin filaments are gradually lost and a medial septin rings appears a the end of anaphase B. 8/

Montage of time-lapse of Spn3-GFP and Sad1-mCherry expressing cells during mitosis. Red asterisk marks the onset of mitosis. Red boxes highlight decreasing Spn3-GFP filament intensity along the cell side throughout mitosis. Sad1-mCherry labels the spindle pole body and indicates mitosic progression.

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Maitreyi Das @daslabpombe.com · 15/02/2026

We further investgated Septin organization in interphase cells. We find short septin filaments at the cell cortex along the long axis in interphase. These filaments are lost in dividing cells as the septins organize to form a medial ring. 7/

Spn3 and Spn1 colocalize to short filaments along the long axis of interphase cells.

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Maitreyi Das @daslabpombe.com · 15/02/2026

In vegetative fission yeast cells, Spn1 and Spn4 are required for cytokinesis as indicated by high septation index in their mutants. Spn2 and 3 are disposable for cytokinesis, but all 4 septins promote proper polarity. These cells disrupt Cdc42 dynamics and grow from one end and are monopolar. 6/

Cells lacking Spn1 and 4 but not Spn2 and 3 show high septation index, indicating cytokinesis defects. But deletion of each of the 4 septins show high monopolarity index, indicating a polarity defect.

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Maitreyi Das @daslabpombe.com · 15/02/2026

In dividing cells and in cell lacking septin Rga4 along the cortex was mobile as determined by FRAP analysis. 5/

G. Montage of Rga4-GFP in spn1+ cells during interphase, during mitosis, and in spn1Δ cells during interphase, taken over a 5-minute time-lapse. Red arrowhead marks an Rga4-GFP puncta at the start of the time-lapse. only interphase spn1+ cells show immobile Rga4-GFP puncta along the cell sides. H. Montage of Rga4-GFP recovery after photobleaching during interphase and mitosis in spn1+ and spn1Δ cells taken in 15-second intervals. Red circles indicate the photobleached region of interest (ROI). Red lightning bolt indicates the time point of photobleaching. Rga4-GFP recovers after photo bleaching in spn1Δ regardless of cell cycle phase but not in spn1+ interphase cells. I. FRAP recovery rates of Rga4-GFP signal intensity within the ROI over time in spn1+ and spn1Δ cells during interphase and mitosis. J. T1/2 fluorescence recovery times of listed conditions.

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Maitreyi Das @daslabpombe.com · 15/02/2026

Years back, we noticed that septin cytoskeleton in interphase decorates the cell sides similar to Rga4. Since septins act as barriers, we investigated their role in Rga4 regulation. We find that in the absence of septins, Rga4 localization in interphase resembles that in dividing cells. 4/

Middle plane images of Rga4-GFP in spn1+ and spn1Δ cells. Red brackets highlight Rga4 distribution along cell sides in interphase cells. Red asterisks highlight dividing cells. Rga4-GFP in interphase cells in spn1Δ appears diffuse and also at teh cell ends.

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Maitreyi Das @daslabpombe.com · 26/12/2025

Merry Christmas all. This year we got to celebrate with our family in India. Housefull of kids, nieces and nephews is so much fun. Kept up with tradition and attended midnight service, lots of plum cake and mutton pulao, karahi chicken and raita. The kids loved it.

Dinner table with mutton pulao, karahi chicken and raita.

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Maitreyi Das @daslabpombe.com · 06/12/2025

The Das lab is well represented at #cellbio2025 in Philly. Come learn more about our research and about the Molecular and Cellular Biology PhD Program at Boston College.

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Maitreyi Das @daslabpombe.com · 06/09/2025

Interestingly, cells that do enter mitosis despite CK666 treatment, show aberrant SPB interaction with the actin ring leading to spindle and nuclear division defects. This suggests that the SPB has an affinity for actin and in the absence of branched actin binds the actin ring instead. 9/

Atb2-mCherry labeled spindle microtubule dynamics in DMSO or CK666-treated synchronized cdc25-22 cells post cell cycle release. Severe bending of microtubules is seen in CK666-treated cells.

3D-reconstruction over time of SPB labeled with cdc11-GFP and the actomyosin ring labeled with Rlc1-tdTomato in CK666-treated cells. One SPB aberrantly interacts with the actin ring and remains at that plane while the other SPB moves towards the cell ends during anaphase.

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Maitreyi Das @daslabpombe.com · 06/09/2025

Branched actin is known to remodel membrane. If it helps fenestration on the NE we should see branched actin elements on the NE and near the SPB. Indeed, she found Fimbrin and Arp2/3 components on the NE and near the SPB. 8/

Fim1-GFP localizes adjacent to Ppc89-mCherry 2 minutes prior to onset of mitosis

Fim1-GFP localizes to Bqt4-mCherry labeled NE.

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Maitreyi Das @daslabpombe.com · 06/09/2025

If CK666 is required for NE fenestration, treating the cells with CK666 should not display mitotic defects. Indeed, in prophase-arrested nda3-KM11 mutants, treatment with ck666 followed by prophase release did not show any mitotic defects. 7/

Loss of branched actin after preprophase arrest does not block mitosis when released. Mitotic progression in nda3-KM311 cells after release from preprophase arrest in DMSO or CK666-treated cells. Quantification of the percentage of cells that progress to mitosis at respective time intervals after the release from prophase arrest.

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Maitreyi Das @daslabpombe.com · 06/09/2025

She asked if this is because the fenestra fails to form in these cells. Indeed, CK666 treated cells retain higher levels of NLS-GFP in the nucleus a hallmark of fenestration defect. 6/

Representative images display accumulation of NLS GFP in the nucleus in DMSO or CK666 treated cut12.1 NLS-GFP strain grown at 36°C for 4 and 5 hours. CK666 treated cells show higher levels of NLS-GFP.

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Maitreyi Das @daslabpombe.com · 06/09/2025

Cut11 recruitment defects typically indicate failure to inset the SPB in the NE. Just before SPB insertion during fenestration, the SUN domain protein Sad1 forms a ring framing the fenestra. Ck666-treated cells fail to form this ring as seen with Structured illumination microscopy. 5/

Redistribution of Sad1-mCherry and Cut11-GFP in synchronized cdc25-22 released into the cell cycle for 30 mins after DMSO or CK666 treatment. CK666 treated failed to form Sad1 and Cut11 rings.

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Maitreyi Das @daslabpombe.com · 06/09/2025

She found that on CK666 treatment, the SPB often failed to recruit the Polo-like kinase Plo1 and the SPB docking protein Cut11. 4/

Plo1-GFP localization in DMSO or CK666-treated synchronous cdc25-22 cells released into the cell cycle. Plo1-GFP localization at the SPB is failed in CK666 phenotype 1, delayed in phenotype 2 and recruited earlier but the mitotic onset is in phenotype 3.

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Maitreyi Das @daslabpombe.com · 06/09/2025

We saw similar defects in mutants of arp3 or actin-bundling protein fimbrin. Fission yeasts undergo closed mitosis and the MTOC or spindle pole body (SPB) duplicates in interphase and just before mitotic onset, is inserted into a fenestra on the nuclear envelope and spindle microtubules nucleate. 3/

DMSO or CK666 treated synchronized cdc25-22 fimΔ cells 30 and 60 minutes after release from cell cycle arrest. bqt4-mCherry labels NE and atb2-mCherry labels microtubules. Red arrowhead shows monopolar spindles. Fimbrin deletion cells show mitotic defects regardless of CK666 treatment.

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Maitreyi Das @daslabpombe.com · 06/09/2025

We noticed that fission yeast cells treated with the Arp2/3 complex inhibitor CK666 often failed mitotic entry. Dhanya confirmed this finding and it was all the clearer in cell-cycle synchronized cells, where CK666 cells often failed to enter mitosis or did so with a significant delay. 2/

Branched actin inhibition blocks or delays mitotic entry. Time-lapse microscopy of DMSO or CK666-treated cdc25-22 synchronized cells released from cell-cycle arrest. Cut11-GFP marks SPB.

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Maitreyi Das @daslabpombe.com · 16/08/2025

G2 phase cells upregulate cellular component biogenesis, cell-wall organization, and plasma membrane maintenance pathways to facilitate bipolar growth. 6/x

Protein-Protein interaction analysis of the downregulated gene in the G1/S phase of cdc10-129 cells using string analysis

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Maitreyi Das @daslabpombe.com · 16/08/2025

Using a combination of GSEA and KEGG analysis, protein-protein interaction networks and validation with cell biology we identified that the nutritional stress response pathway that promotes G1-arrest is upregulated in G1/S phase and prevents precocious bipolar growth. 5/x

Protein-Protein interaction analysis using string for upregulated genes in the G1/S phase of cdc10-129 cells using string

Cell morphological analysis for stress-pathway marker spk1∆ mutant using calcofluor staining. The spk1∆ mutants are precociously bipolar

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Maitreyi Das @daslabpombe.com · 16/08/2025

To identify the factors promoting the transition from monopolar to bipolar growth, we analyzed differential gene expression patterns between G1/S and G2 phase cells. We used the cdc10-129 mutants that arrest in G1/S under restrictive conditions. 4/x

Experimental design for high-throughput mRNA sequencing. cdc10-129 mutants were arrested in G1/S and then synchronized in G2.

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Maitreyi Das @daslabpombe.com · 16/08/2025

Cell morphological analysis for stress-pathway marker spk1∆ mutant using calcofluor staining. Spk1 deletion cells show precocious bipolar growth.

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Maitreyi Das @daslabpombe.com · 11/06/2025

This was my 5yo at a meeting I had to attend way back. The last time I had to tag him along at a lecture I gave, he was 10. He told me I was a very good teacher because students did not seem confused. 😂

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Maitreyi Das @daslabpombe.com · 01/06/2025

Our first peony ever. Planted the bulb last year.

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Maitreyi Das @daslabpombe.com · 19/05/2025

It's my favorite time of the year!🎉 Commencement and graduate hooding. Congratulations to Daslab students, Dr. Bethany Campbell and Dr. Marcus Harrell. Also Dr. Harrell was awarded the dissertation award in science and math. Well done.

Dr. Bethany Campbell and Dr. Maitreyi Das at the graduate hooding ceremony.

Dr. Marcus Harrell and Dr. Maitreyi Das at the graduate hooding ceremony.

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Maitreyi Das @daslabpombe.com · 17/05/2025

With all the craziness around us these days, we need moments of pure joy. I found mine last night at the Indian Ocean concert at the Somerville theatre. Took me back to my IIT mood indigo days.

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Maitreyi Das @daslabpombe.com · 02/05/2025

The Das lab was well represented at the Hamilton symposium and undergraduate research day at Boston College. Erik Flores-Reyes, Olivia Chinsen and Uma Patel presented their research.

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Maitreyi Das @daslabpombe.com · 28/03/2025

How do we navigate this storm? From the @ascbiology.bsky.social newsletter.

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Maitreyi Das @daslabpombe.com · 16/02/2025

We bid farewell to Dr. Samridhi Pathak who starts a new position at Sanofi next week. Goodluck Sam and wish you the very best.

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Maitreyi Das @daslabpombe.com · 14/02/2025

Happy Valentine's Day! Here is a pombe Valentine. In these hard times do not forget to take care of yourself and those around you. You are loved and you matter.

pombe Valentine. Septin proteins are localized in the shape of a heart in a fission yeast cell.

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Maitreyi Das @daslabpombe.com · 11/01/2025

Reminds me of this. "I see what you mean" at the Denver Convention center.

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Maitreyi Das @daslabpombe.com · 30/12/2024

The most exquisite place in this island. Crystal/Fantasy caves. #Bermuda

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Maitreyi Das @daslabpombe.com · 19/12/2024

The Das lab is bidding goodbye to two of its dearest members. They will be sorely missed. Dr. Bethany Campbell will start a visiting faculty position at Maryville College in TN and Dr. Marcus Harrell will start a postdoctoral position at St. Jude Children's hospital. We wish them the very best. ❤️

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Maitreyi Das @daslabpombe.com · 18/12/2024

#cellbio2024 was great. Lots of good science, community, networking, and inspiration. Looking forward to the next year in Philly.

Das lab members past and present at Cellbio2024

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Maitreyi Das @daslabpombe.com · 17/12/2024

Please join us today at 3:15pm for the #WICB Panel and Networking Event: Academic Evolution: Rethinking Metrics, Rewriting Rules. Room 25b. #cellbio2024 @ascbiology.bsky.social

WICB Panel and Networking Event: Academic Evolution: Rethinking Metrics, Rewriting Rules AT 3:15PM room 25b at Cellbio2024.

Panelists: Drs. Jade Moore, Bernier Pulverer, Beverly Wendland, Erin Cech, Sara Wong, JoAnn Trejo.

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