Alex Ludwig
@alexludwig.bsky.social
Cell biologist and nature lover interested in epithelial cell junctions, mechanobiology, and cell polarity. Asst Prof at NTU Singapore.
Check out the ALab homepage:
https://blogs.ntu.edu.sg/alabntusg/
Check out the ALab homepage:
https://blogs.ntu.edu.sg/alabntusg/
Entzugserscheinungsangst :)
April 17, 2025 at 2:02 PM
Entzugserscheinungsangst :)
Why am I not surprised…
March 17, 2025 at 12:50 PM
Why am I not surprised…
Altogether we propose that the fusion of VACs with the AMIS provides an efficient mechanism for the rapid specification of apical domain identity. In addition, Pals1 and PatJ appear to be critical for VAC fusion at the AMIS, possibly due to their role in regulating the apical actin cytoskeleton.
March 7, 2025 at 7:41 AM
Altogether we propose that the fusion of VACs with the AMIS provides an efficient mechanism for the rapid specification of apical domain identity. In addition, Pals1 and PatJ appear to be critical for VAC fusion at the AMIS, possibly due to their role in regulating the apical actin cytoskeleton.
Finally, we asked how VAC exocytosis at the AMIS is regulated and found that loss of the Crb complex proteins Pals1 or PatJ results in the intracellular accumulation of VACs and severe defects in lumen formation. Apical actin levels and the apical cell cortex were markedly altered in PatJ KO cells.
March 7, 2025 at 7:41 AM
Finally, we asked how VAC exocytosis at the AMIS is regulated and found that loss of the Crb complex proteins Pals1 or PatJ results in the intracellular accumulation of VACs and severe defects in lumen formation. Apical actin levels and the apical cell cortex were markedly altered in PatJ KO cells.
We further present evidence that VACs arise from the internalisation of microvilli-enriched membrane pits at the ECM facing side of cell doublets. How these membrane pits are internalised and how VACs are trafficked to and fuse with the AMIS is currently unclear.
March 7, 2025 at 7:41 AM
We further present evidence that VACs arise from the internalisation of microvilli-enriched membrane pits at the ECM facing side of cell doublets. How these membrane pits are internalised and how VACs are trafficked to and fuse with the AMIS is currently unclear.
We then analysed lumen initiation in MDCK 3D cultures. Using LM and EM we identified intracellular VACs and observed fusion events of VACs with the Apical Membrane Initiation Site (AMIS). Interestingly, VAC fusion at the AMIS was again coordinated with the formation of cell-cell junctions.
March 7, 2025 at 7:41 AM
We then analysed lumen initiation in MDCK 3D cultures. Using LM and EM we identified intracellular VACs and observed fusion events of VACs with the Apical Membrane Initiation Site (AMIS). Interestingly, VAC fusion at the AMIS was again coordinated with the formation of cell-cell junctions.
Interestingly, our time-resolved proteome revealed distinct recruitment profiles of Rho and Ras GTPases, tight junction membrane and scaffolding proteins, as well as apical proteins, providing new insight into the temporal execution of cell polarity development.
March 7, 2025 at 7:41 AM
Interestingly, our time-resolved proteome revealed distinct recruitment profiles of Rho and Ras GTPases, tight junction membrane and scaffolding proteins, as well as apical proteins, providing new insight into the temporal execution of cell polarity development.
This set of experiments demonstrated that apical lumens are initiated by the exocytosis of large intracellular organelles at nascent cell-cell contact sites. Such organelles contain a pre-assembled microvilli-rich cortex and are known as Vacuolar Apical Compartments (VACs), or apicosomes.
March 7, 2025 at 7:41 AM
This set of experiments demonstrated that apical lumens are initiated by the exocytosis of large intracellular organelles at nascent cell-cell contact sites. Such organelles contain a pre-assembled microvilli-rich cortex and are known as Vacuolar Apical Compartments (VACs), or apicosomes.
To understand how apical lumen initiation and cell-cell junction assembly are coordinated, we initially analysed polarity development using the calcium switch assay, serial section TEM, and time-resolved proximity proteomics with our favourite enzyme APEX2. This is all done in MDCK cells.
March 7, 2025 at 7:41 AM
To understand how apical lumen initiation and cell-cell junction assembly are coordinated, we initially analysed polarity development using the calcium switch assay, serial section TEM, and time-resolved proximity proteomics with our favourite enzyme APEX2. This is all done in MDCK cells.