Biochemical Assay Scientist - AlphaScreen Expert

Pliant Therapeutics; South San Francisco (CA); On-site; USD 125,000 - 138,000; Full time

Job summary

Pliant Therapeutics in South San Francisco is seeking an Associate Scientist I to develop, optimize, and run biochemical binding assays (AlphaScreen/AlphaLISA) for medium- to high-throughput screening, generating potency and selectivity data to guide medicinal chemistry decisions.

This hands-on role reports to the Senior Vice President, Research and requires expertise in assay development, screening formats, and data analysis, with a focus on robust signal windows and reproducibility.

Qualifications

• BS in Biochemistry/ Biology/ Chemistry with 7+ years in pharma, or MS with 5+ years.
• Hands-on AlphaScreen/AlphaLISA assay development and troubleshooting.
• Experience in 384- and 1536-well HTS formats.
• Proficiency with liquid handling and plate readers for Alpha detection.
• Familiarity with high-content imaging (Operetta CLS).
• Strong data analysis and curve-fitting skills.
• Excellent ELN documentation and independent collaboration.

Responsibilities

• Design, develop and optimize biochemical binding assays, with a focus on AlphaScreen/AlphaLISA proximity formats (e.g., protein–protein and protein–ligand interaction and competition assays).
• Miniaturize and transfer assays to 384- and 1536-well formats; validate them for screening using Z′, signal-to-background, CV and reference‑compound reproducibility.
• Support cell-based assays, including mammalian cell culture, plating and compound treatment, cell density and workflow optimization, acquire and analyze images on high-content imaging systems.
• Execute medium-to high-throughput screening campaigns and dose-response (IC50/EC50) profiling to support hit identification and SAR.
• Identify and triage assay interference using counter-screens and orthogonal formats.
• Manage compound and sample workflows, including plate preparation and retrieval from automated sample storage systems.
• Analyze, QC and report data in Scilligence; maintain complete, contemporaneous ELN records.
• Write and maintain SOPs and assay reports; present results and issues clearly at project team meetings.
• Qualify critical reagents (proteins, antibodies, tagged constructs) in partnership with protein sciences.

Skills

AlphaScreen/AlphaLISA

HTRF/TR-FRET

Data analysis

Cell culture

Automation scripting

Education

BS in Biochemistry/ Biology/ Chemistry

MS with 5+ years

Tools

i5 BIOMEK

Tempest

EnVision

PHERAstar

Operetta CLS

GraphPad Prism

Genedata Screener

KNIME

Python

R

Job description

Pliant Therapeutics in South San Francisco is seeking an Associate Scientist I to develop, optimize, and run biochemical binding assays (AlphaScreen/AlphaLISA) for medium- to high-throughput screening, generating potency and selectivity data to guide medicinal chemistry decisions.

This hands-on role reports to the Senior Vice President, Research and requires expertise in assay development, screening formats, and data analysis, with a focus on robust signal windows and reproducibility.