Patrick A Sandoz

KTH Royal Institute of Technology | KTH · Department of Applied Physics

Tumor diversity and rarity of patient tumor material negatively contribute to the development of new effective treatments for sarcomas. As a high proportion of sarcoma patients presents inherent or acquired chemo-resistance, immune checkpoint inhibitors could represent an alternative for these cases. However, only a small fraction of sarcoma patien...

The complex architecture of the endoplasmic reticulum (ER) comprises distinct dynamic features, many at the nanoscale, that enable the coexistence of the nuclear envelope, regions of dense sheets and a branched tubular network that spans the cytoplasm. A key player in the formation of ER sheets is cytoskeleton-linking membrane protein 63 (CLIMP-63)...

Vγ9Vδ2 is the largest γδ T cell subset in human peripheral blood. These cells get activated and proliferate in response to phosphoantigens produced by infected or tumour transformed cells. Although Vγ9Vδ2 T cells have shown evidence of innate-like cytotoxicity, their modus operandi remains poorly understood. In this work, we have used single-cell i...

Here, we present a methodology based on multiplexed fluorescence screening of two- or three-dimensional cell cultures in a newly designed multichambered microwell chip, allowing direct assessment of drug or immune cell cytotoxic efficacy. We establish a framework for cell culture, formation of tumor spheroids, fluorescence labeling, and imaging of...

Miniaturization of cell culture substrates enables controlled analysis of living cells in confined micro-scale environments. This is particularly suitable for imaging individual cells over time, as they can be monitored without escaping the imaging field-of-view (FoV). Glass materials are ideal for most microscopy applications. However, with curren...

The complex architecture of the endoplasmic reticulum (ER) comprises distinct dynamic features, many at the nanoscale, that enable the coexistence of the nuclear envelope, regions of dense sheets and a branched tubular network that spans the cytoplasm. A key player in the formation of ER sheets is cytoskeleton-linking membrane protein 63 (CLIMP-63)...

Many biochemical reactions require controlled recruitment of proteins to membranes. This is largely regulated by posttranslational modifications. A frequent one is S-acylation, which consists of the addition of acyl chains and can be reversed by poorly understood acyl protein thioesterases (APTs). Using a panel of computational and experimental app...

Many biochemical reactions occur at the membrane interfaces. The proper control of these reactions requires spatially and temporally controlled recruitment of protein complexes. These assemblies are largely regulated by post-translational modifications and a frequent one is S-acylation, which consists of the addition of medium length acyl chains. R...

Although 𝛾𝛿TCRs were discovered more than 30 yr ago, principles of antigen recognition by these receptors remain unclear and the nature of these antigens is largely elusive. Numerous studies reported that T cell hybridomas expressing several V𝛾1-containing TCRs, including the V𝛾1V𝛿6 TCR of 𝛾𝛿NKT cells, spontaneously secrete cytokines. This property...

Holo-tomographic microscopy (HTM) is a label-free microscopy method reporting the fine changes of a cell’s refractive indices (RIs) in three dimensions at high spatial and temporal resolution. By combining HTM with epifluorescence, we demonstrate that mammalian cellular organelles such as lipid droplets (LDs) and mitochondria show specific RI 3D pa...

The development of a fluorescent LCK inhibitor that exhibits favourable solvatochromic properties upon binding the kinase enzyme is described. Fluorescent properties were realised through the inclusion of a Prodan‐derived fluorophore into the pharmacophore of the ATP‐competitive kinase inhibitor. Fluorescence titration experiments exemplify the sol...

The development of a fluorescent LCK inhibitor that exhibits favourable solvatochromic properties upon binding the kinase enzyme is described. Fluorescent properties were realised through the inclusion of a Prodan‐derived fluorophore into the pharmacophore of the ATP‐competitive kinase inhibitor. Fluorescence titration experiments exemplify the sol...

The endoplasmic reticulum (ER) has a complex morphology generated and maintained by membrane-shaping proteins and membrane energy minimization, though not much is known about how it is regulated. The architecture of this intracellular organelle is balanced between large, thin sheets that are densely packed in the perinuclear region and a connected...

Holo-tomographic microscopy (HTM) is a label-free non-phototoxic microscopy method reporting the fine changes of a cell's refractive indexes (RI) in 3D. By combining HTM with epifluorescence, we demonstrate that cellular organelles such as Lipid droplets and mitochondria show a specific RI signature that distinguishes them with high resolution and...

The reversible modification of cysteine residues by thioester formation with palmitate (S-palmitoylation) is an abundant lipid post-translational modification (PTM) in mammalian systems. S-palmitoylation has been observed on mitochondrial proteins, providing an intriguing potential connection between metabolic lipids and mitochondrial regulation. H...

Source data for all figures.

(A) Half-life of DHHC6 in different palmitoylation states. The half-life was estimated from the decay rate constant obtained through parameter estimation. The half-life is calculate as: ln(2)/kd. (B) Total amount of protein in steady state relative to WT for WT and CAA mutant in different conditions. The table shows the total protein in steady stat...

(A) Model reactions. The model of DHHC6 palmitoylation contains 35 different reactions, describing synthesis, folding, degradation, and the enzymatic reactions of DHHC6 palmitoylation/depalmitoylation. In the following table we describe in detail how the rates for those reactions are calculated. (B) Mass balance equations. The following table descr...

(A) Parameters used for stochastic simulations. The following parameters were obtained through the conversion of the deterministic parameters estimated by the GA (see Dallavilla et al., 2016). (B) Stoichiometric matrix used for stochastic simulations. In the following table we define the stoichiometry and the directionality of the reactions of the...

Results of stochastic simulation when APT2 is silenced. The table shows the average number of passages of a DHHC6 molecule in the different palmitoylation states when APT2 is silenced. The time spent in each state is also reported.

S-Palmitoylation is the only reversible post-translational lipid modification. Knowledge about the DHHC family of palmitoyltransferases is very limited. Here we show that mammalian DHHC6, which modifies key proteins of the endoplasmic reticulum, is controlled by an upstream palmitoyltransferase, DHHC16, revealing the first palmitoylation cascade. C...

S-Palmitoylation is the only reversible post-translational lipid modification. Knowledge about the DHHC family of palmitoyltransferases is very limited. Here we show that mammalian DHHC6, which modifies key proteins of the endoplasmic reticulum, is controlled by an upstream palmitoyltransferase, DHHC16, revealing the first palmitoylation cascade. C...

Cellular functions are largely regulated by reversible post-translational modifications of proteins which act as switches. Amongst these, S-palmitoylation is unique in that it confers hydrophobicity. Due to technical difficulties, the understanding of this modification has lagged behind. To investigate principles underlying dynamics and regulation...

In 1995, in the Biochemical Society Transactions, Mundy published the first review on CLIMP-63 (cytoskeleton-linking membrane protein 63) or CKPA4 (cytoskeleton-associated protein 4), initially just p63 [1]. Here we review the following 20 years of research on this still mysterious protein. CLIMP-63 is a type II transmembrane protein, the cytosolic...

Control of particles/cells and the surrounding fluid is enabling toward the purification of complex cellular samples, which still remains a bottleneck for point-of-care diagnostic devices. We explore a newly developed approach to engineer fluid stream motion while simultaneously controlling particles using inertial lift force. We use inertial flow...

Super-resolution optical fluctuation imaging (SOFI) provides an elegant way of overcoming the diffraction limit in all three spatial dimensions by computing higher-order cumulants of image sequences of blinking fluorophores acquired with a classical widefield microscope. Previously, three-dimensional (3D) SOFI has been demonstrated by sequential im...

Enzymatic signal amplification based on fluorogenic substrates is commonly used for immunoassays, however, when transitioning these assays to a digital format in water-in-mineral oil emulsions such amplification methods have been limited by the leakage of small reporting fluorescent probes. In the present study we used a microfluidic system to stud...

We report a new technique to improve signal fidelity for implementing on-chip digital immunoassays running on a cell-phone. The assay targets the human immunodeficiency virus (HIV) p24 capsid protein to quantify viral load as part of a compact device for point of care (POC) testing. The sample is digitized as water-in-oil droplets and integrates ad...