Junior Specialist _ Membrane Transporter and Enzyme Biochemistry

The Nicklisch Lab (PI: Dr. Sascha

C. T. Nicklisch), Department of Environmental Toxicology, University of California, Davis, seeks a Junior Specialist to support research on the mechanistic role of ABC drug transporters and cytochrome P450 (CYP) enzymes in the disposition and toxicity of drugs and environmental chemicals. The successful candidate will focus on recombinant expression and purification of membrane transport proteins and CYP enzymes across multiple host systems, and on functionally characterizing their interactions with small molecules using activity assays.

Lab website:
Nicklisch Lab | Understanding chemical uptake, disposition, and accumulation in organisms

Core technical focus

• Clone and codon-optimize genes encoding ABC drug transporters (e.g., P-glycoprotein/ABCB1, BCRP/ABCG2) and CYP enzymes from multiple organisms; design gene-specific and degenerate primers from sequence alignments.
• Express recombinant transporters and CYP enzymes in bacterial (E. coli), yeast (Pichia pastoris), and insect-cell (baculovirus/Sf9) systems using shake-flask and bioreactor/fermentation cultivation.
• Purify membrane proteins by cell disruption, differential and ultracentrifugation-based membrane fractionation, and affinity, ion-exchange, and size-exclusion FPLC (Äkta/Bio Rad); prepare inside-out membrane vesicles for functional assays.
• Verify protein expression, purity, and identity by general protein-biochemistry methods, including SDS-PAGE, Western blot analysis, and total-protein quantification.
• Characterize transporter–small molecule interactions by membrane-vesicle ATPase activity assays (e.g., vanadate-sensitive activity with inorganic-phosphate detection), including substrate, inhibitor, and modulator profiling.
• Establish and perform CYP enzyme activity assays for proteins purified from different organisms.
• Prepare lipid and protein stock solutions (rotary evaporation, lyophilization); calibrate and operate pH meters, analytical balances, and related instrumentation.

• Develop and implement experimental designs and protocols under strict quality-assurance and safety guidelines; independently develop backup plans for experimental pitfalls (e.g., alternative expression hosts or detection strategies).
• Critically read the scientific literature to inform best-practice protocols.
• Gather, prepare, and label reagents, stock solutions, and hazardous-chemical dilutions; record data completely on datasheets and in spreadsheets; properly dispose of hazardous substances; clean and sterilize supplies.
• Analyze kinetic data and test hypotheses using appropriate statistics (e.g., nonlinear regression, ANOVA, t-tests); generate graphs and summary tables.
• Keep the PI apprised of problems, including failed assays, delays, and out-of-spec calibrations; present ongoing results at weekly lab meetings.
• Maintain safe laboratory conditions: follow all safety procedures, wear required PPE, and identify and report hazards.

• Contribute to conference posters and presentations (e.g., Society of Toxicology, SETAC, Biophysical Society) and to peer-reviewed publications, including optimized expression/purification protocols and functional characterization of active proteins.

• Mentor undergraduate and graduate students and visiting scientists in the techniques above; assist with written and oral research dissemination.

• Bachelor's degree in biochemistry, molecular biology, biotechnology, or a related field, with laboratory experience in molecular biology, microbiology/biotechnology, and/or toxicology-related research.
• Record-keeping skills to accurately document detailed research data.
• Skills to perform repetitive laboratory work with attention to detail and limited supervision, including pipetting small volumes, calculating and preparing concentrations and serial dilutions, and handling chemicals of varying toxicity.
• Proficiency with Word, Excel, and a data-analysis package (Origin, Sigma Plot, JMP, Graph Pad, or equivalent).
• Ability to work independently and as part of a team.