Rhoderick E. Brown Ph.D.
Rhoderick Brown is the leader of the Membrane Biochemistry & Molecular Biophysics section at the Hormel Institute. Prof. Brown received his B.A. degrees in Chemistry and Zoology from the University of North Carolina at Chapel Hill and his Ph.D. degree in Biochemistry from Wake Forest University. He carried out post-doctoral research in the laboratories of Prof. Thomas E. Thompson and Thomas W. Tillack at the University of Virginia.
- University of North Carolina, Chapel Hill NC
- Chemistry & Zoology
- Wake Forest University, Winston Salem NC
- University of Virginia, Charlottesville VA
Personal interests and hobbies
His outside interests in hiking, canoeing, camping, and cycling began many years ago in western North Carolina.
- Biophysical Society
- American Society for Biochemistry and Molecular Biology
- Membrane Structure & Assembly Subgroup, Biophysical Society
- Ad hoc NIH Study Section member and consultant
- National Science Foundation reviewer
- Japan Society for Promotion of Science reviewer
- Chemistry & Physics of Lipids Editorial Board
- Journal of Lipids Editorial Board
- Sphingolipid transfer protein structure and function in programmed cell death pathways, inflammation, and cancer
- Cytoplasmic phospholipase A2 structure and function in inflammation and sepsis
- Regulation of amphitropic membrane protein translocation by lipid binding domains
- Sphingolipid roles in raft microdomain formation and stabilization in membranes
Mishra SK, Gao Y-G, Deng Y, Chalfant CE, Hinchcliffe EH, Brown RE (2018) CPTP: A sphingolipid transfer protein that regulates autophagy and inflammasome activation, Autophagy (published on-line 02/21/2018) https://doi.org/10.1080/15548627.2017.1393129
Zhai X, Gao Y-G, Mishra SK, Simanshu DK, Boldyrev IA, Benson LM, Bergen III HR, Malinina L, Mundy J, Molotkovsky JG, Patel DJ, Brown RE (2017) Phosphatidylserine stimulates ceramide-1-phosphate (C1P) intermembrane transfer by C1P transfer proteins,
J. Biol. Chem. 292, 2531–2541
Malinina L, Patel DK, Brown RE (2017) How α-Helical Motifs Form Functionally Diverse Lipid-Binding Compartments, Annu. Rev. Biochem. 86, 609-636
Malinina L*, Simanshu DK, Zhai X, Samygina VR, Kamlekar RK, Kenoth R, Ochoa-Lizarralde B, Malakhova ML, Molotkovsky JG, Patel DK*, Brown RE* (2015) Sphingolipid transfer proteins defined by the GLTP-fold. Quart. Rev. Biophys. 48, 281-322 (*cspd. authors)
Simanshu DK, Zhai X, Munch D, Hofius D, Markham JE, Bielawski J, Bielawska A, Malinina L, Molotkovsky JG, Mundy J*, Patel DS*, Brown RE*. (2014) Arabidopsis accelerated-cell-death11, ACD11, is a ceramide-1-phosphate transfer protein and intermediary regulator of phytoceramide levels. Cell Reports 6:388-399 (*cspd. authors)
Zhai X, Boldyrev IA, Mizuno NK, Momsen MM, Molotkovsky JG, Brockman HL*, Brown RE* (2014) Nanoscale packing differences in sphingomyelin and phosphatidylcholine revealed by BODIPY fluorescence in monolayers: physiological implications. Langmuir 30, 3154-3164 (*cspd. authors)
Zhai X, Momsen WE, Malakhov DA, Boldyrev IA, Momsen MM, Molotkovsky JG*, Brockman HL*, Brown RE* (2013) GLTP-fold interaction with planar phosphatidylcholine surfaces is synergistically stimulated by phosphatidic acid and phosphatidylethanol¬amine, J. Lipid Res. 54, 1103-1113 (*cspd. authors).
Simanshu DK, Kamlekar R-K, Wijesinghe DS Zou X, Zhai X, Mishra SK, Molotkovsky JG Malinina L, Hinchcliffe EH*, Chalfant CE*, Brown RE*, Patel DS*. (2013) Non-vesicular trafficking by a ceramide-1-phosphate transfer protein regulates eicosanoids.
Nature 500:463-467 (*cspd. authors)
Complete listing of published research works by Rhoderick E Brown is available at: https://experts.umn.edu/en/persons/rhoderick-e-brown/publications
ORCID ID (for REB): 0000-0002-7337-3604
Primary Research Areas
The following avenues of research are currently being actively pursued:
• Regulation of Inflammation by Sphingolipid (C1P) and Phosphoglyceride (PIP2) Activators of Cytoplasmic Phospholipase A2α: Insights by Structure/Function Analyses
We are currently investigating the molecular basis by which human cytoplasmic phospholipase A2 (cPLA2α) initially promotes inflammation but then subsequently helps reverse and resolve sepsis. Gaining new insights could lead to new avenues for treating this pathological process and inflammation associated with other pathologic conditions such as cancer, diabetes and dementia. These recently initiated studies are being pursued in collaboration with Charles Chalfant (USF), Dinshaw Patel (Memorial Sloan Kettering Cancer Ctr.), and Edward (Ted) Hinchcliffe (Univ. Minnesota). They extend previous collaborative work involving ceramide-1-phosphate (C1P) transfer protein (CPTP). The previous work led to the model, that first appeared in our 2013 Nature paper (right panel), showing how CPTP depletion in cells can stimulate the action of cPLA2α to promote pro-inflammatory eicosanoid production.
In recent studies, we have determined that CPTP functions an endogenous regulator of autophagy and of inflammasome assembly to help drive interleukin release (IL1B and IL18). The report describing this work was published recently in Autophagy.
o Mishra SK, Gao Y-G, Deng Y, Chalfant CE, Hinchcliffe EH, Brown RE (2018) CPTP: A sphingolipid transfer protein that regulates autophagy and inflammasome activation, Autophagy (published on-line 02/21/2018) https://doi.org/10.1080/15548627.2017.1393129
• Sphingolipid Trafficking by GLTP Superfamily Members: Differential Regulation and Targeting to Select Membranes via Specific Lipid Docking Sites
In ongoing studies, we are identifying and characterizing surface sites that function as lipid interaction sites to activate and potentially guide the intracellular localization of various GLTP-fold family members. Some of the work was recently reported in The Journal of Biological Chemistry
o Zhai X, Gao Y-G, Mishra SK, Simanshu DK, Boldyrev IA, Benson LM, Bergen III HR, Malinina L, Mundy J, Molotkovsky JG, Patel DJ, Brown RE (2017) Phosphatidylserine stimulates ceramide-1-phosphate (C1P) intermembrane transfer by C1P transfer proteins, J. Biol. Chem. 292, 2531–2541
• GLTP-fold Structural Features That Regulate Sphingolipid Selectivity and Enable Formation of Sphingolipid Binding Compartments
o Structure/Function Analysis of FAPP2 Glycolipid Transfer Protein Homology Domain (GLTPH)
Currently under revision for JBC is a new paper describing the first crystal structure of the GLTPH domain of FAPP2. The work reveals previously unknown regulatory elements that occur in the GLTP-fold and was pursued in collaboration with Dr. Lucy Malinina.
o Annual Review of Biochemistry (invited review)
Malinina L, Patel DK, Brown RE (2017) How α-Helical Motifs Form Functionally Diverse Lipid-Binding Compartments, Annu. Rev. Biochem. 86, 609-636
o Quarterly Reviews of Biophysics (invited review)
Malinina L, Simanshu DK, Zhai X, Samygina VR, Kamlekar RK, Kenoth R, Ochoa-Lizarralde B, Malakhova ML, Molotkovsky JG, Patel DK, Brown RE (2015) Sphingolipid transfer proteins defined by the GLTP-fold. Quart. Rev. Biophys. 48, 281-322.
Structure and Function of Glycolipid Transfer Proteins (GLTP). The molecular cloning and crystalliza¬tion of human GLTP in our lab sparked major advances by enabling X-ray determination of GLTP molecular structure in collaboration with the DJ Patel lab (Sloan Kettering). The novel GLTP-fold is highly conserved among eukaryotes but sometimes displays localized conformational features that alter the glycolipid selectivity such as in a fungal GLTP ortholog. The structure/function insights have aided the successful development of ‘designer human GLTPs’ engineered by point mutations to achieve more focused glycolipid selectivity. The findings have also guided current ideas regarding subtle structural features in the GLTP-fold that control the glycolipid selectivity differences of human FAPP2 and GLTP.
2. Structure and Function of Ceramide-1-Phosphate Transfer Proteins (CPTPs). This research provided the first insights into human ceramide-1-phosphate transfer protein (CPTP), which uses a GLTP-fold with an evolutionarily-modified lipid recognition center and is coded on chromosome 1 (locus 1p36.33). After verifying the existence of CPTP mRNA predicted by computer annotation of the human genome, we cloned CPTP, solved its molecular structure complexed with various species of C1P in collaboration with DJ Patel lab (Sloan Kettering), and discovered that CPTP can modulate C1P levels in the trans-Golgi and regulate cPLA2α activity that drives pro-inflammatory eicosanoid production in collaboration with the EH Hinchcliffe (UMN) and CE Chalfant (USF) labs. In parallel, we studied the structure and function of Arabidopsis ACD11, a plant ortholog of human CPTP, and showed its essential role in regulating both C1P and ceramide levels in Arabidopsis in collabora¬tion with the J Mundy (U Copenhagen) and DJ Patel labs. The findings provide the first evidence for the existence of a new CPTP protein family, with a modified GLTP-fold, within the GLTP superfamily.
3. Molecular and Cell Biological Aspects of GLTPs & CPTPs. GLTP gene organiza¬tion, transcriptional status, phylogenetic, and evolutionary relationships has been studied in our lab. The single-copy GLTP gene on chromosome 12 (locus 12q24.11) is the source of transcribed human GLTP. Phylogenetic and evolutionary analyses show a 5-exon/4-intron gene organizational pattern that is highly conserved in therian mammals and other vertebrates. A second intronless GLTP gene on chromosome 11 (locus 11p15.1) is a nontranscribed pseudogene present only in primates, consistent with recent evolution¬ary development. We also identified and characterized the constitutive and basal human GLTP gene promoters. Four GC-boxes were shown to be functional Sp1/Sp3 transcription factor binding sites. Mutation of one GC-box was particularly detrimental to GLTP transcriptional activity. Sp1/Sp3 RNA silencing and mithramycin-A treat¬ment significantly affected GLTP promoter activity. Among various sphingolipids, only ceramide induces GLTP promoter activity and partially blocked activity decreases induced by Sp1/Sp3 RNAi, thereby linking human GLTP expression to sphingolipid homeostasis through ceramide. GLTP over¬expression in epithelial cells (HeLa and HEK-293) is found to induce cell rounding. Cell shape is unaffected by overexpression of W96A-GLTP, a ligand-site point mutant with abrogated glyco¬lipid transfer activity. The round adherent cells exhibit diminished motility in wound healing assays and an inability to endocytose cholera toxin but remain viable and non-apoptotic. Interaction of GLTP with δ-catenin accelerates the transition to the rounded phenotype while δ catenin overexpression alone induces dendritic outgrowths. CPTP depletion, but not GLTP depletion, induces pro-inflammatory eicosanoid production. Ongoing studies now show CPTP involvement in triggering autophagy by upregulation of autophagosome formation and inflammasome assembly/activation to drive interleukin release.
4. Development of new BODIPY-lipid probes for membrane research. In collaboration with JG Molotkovsky and Ivan Boldyrev (Russian Acad. Sciences), we characterized lipid fluorophores with BODIPY omega-linked to a fatty acid of phospho¬glycer¬ides or sphingolipids for useful¬ness in membrane studies. We showed how these BODIPY probes (now marketed as TopFluorTM by Avanti Polar Lipids) can provide nanoscale insights into lipid organiza¬tion and mixing in monolayers. This work relied on a modified Langmuir film balance, developed in the HL Brockman lab, UMN, that acquires fluorescence spectra, i.e. >200 emission spectra of BODIPY-labeled-PC, SM, or -GalCer during a single monolayer compression scan. The concen¬tra¬tion-dependent emission changes of BODIPY-lipids that occur simultaneously with acquisition of the surface pressure versus molecular area isotherms provide nano¬scale insights into the lipid packing and lateral mixing.
5. Sphingolipid-Cholesterol Rafts: Physical characterization of their liquid-ordered (LO) packing state. We investigated the mixing behavior of glyco¬sphingolipids and sphingomyelins with phospha-tidyl¬cholines and cholesterol to gain insights into ‘raft’ microdomain physical properties. We showed that SL aliphatic chain saturation and head¬group chemistry both are key factors regulating packing with other membrane lipids. The lack of commercial availability in the 1990s prompted us to synthesize chain-pure SLs. Using a high-precision, automated, Langmuir film balance [collaboration w/ HL Brockman lab (UMN)], we found that lipid lateral packing elasticity (surface compressional modulus; Cs-1) provides a quantifiable measure of the ordered but nonrigid environ¬ment in SL-cholesterol mixtures, i.e. liquid-ordered phase, that characterizes lipid rafts. Cs-1 reflects a macroscopic pro¬p¬erty of the lipid phase state. To gain molecular sights, we used a custom-modified Langmuir film balance that acquires >200 fluorescence spectra during a single monolayer compression scan. The concentra¬tion-dependent emission changes of BODIPY-PC during mono¬layer compression revealed nano¬scale differences in the lipid packing/phase states of sphingo¬myelins versus saturated-chain phophatidylcholines.
6. Regulation of sphingolipid transmembrane distribution by bilayer curvature and lipid composition. Using NMR approaches, we studied how membrane curvature and lipid composition of membrane bilayers regulate the transbilayer distribution of glycosphingolipids. This work showed that sphingomyelin lateral interactions with simple glycosphingolipids play a major role in regulating glycolipid transbilayer distributions and pool size in the outer and inner leaflets of bilayer vesicles.
7. Cryo-EM studies of lipid nanotubes and ribbons formed via chirally-regulated lateral interactions of sphingolipids. Using freeze-fracture electron microscopy and differential scanning calorimetry, we characterized fundamental biophysical features of glycosphingolipids (e.g. galactosyl-ceramide) synthetically modified to have various homogenously monounsaturated acyl chains. We discovered that galactosylceramides acylated with nervonoyl chains (24:1) form bilayer helical ribbons that self-seal into bilayer nanotubes. The chiral interactions that generate the helical packing within the bilayer nanotubes were found to support and enhance 2D-helical crystallization of proteins in collaborative studies with the RA Milligan lab (Scripps Res. Inst.).
8. Spontaneous Lipid Transfer Processes. Our interest in spontaneous lipid intermembrane transfer processes that can occur in the absence of proteins began as post-doc studies initiated in the T.E. Thompson lab. This kind of lipid transfer can occur via lipid monomer transfer through the aqueous phase from one membrane to another or via transient collisional contacts between membrane vesicles or hemi-fusion between membrane vesicles.
IJ Holton Endowed Professorship, 2018
Sphingolipid transfer protein research featured in the ‘Lipid News’ section of the March 2014 issue of ASBMB TODAY (http://www.asbmb.org/uploadedFiles/ASBMBToday/Content/Archive/ASBMBToday-2014-03.pdf)
Research support: longstanding support by NIGMS-GM45228 and Hormel Foundation; additional support by NCI- CA121493, NHLBI-HL08214, NHLBI-HL125353 and Southern Minnesota Paint-the-Town Pink.