(Principal) Senior Scientist, Receptor & Cell Biology

About Nosis Bio

Nosis Bio is a well-funded biotech startup exclusively focused on cell-specific delivery of RNA therapeutics. We are an all-scientist team of biologists, chemists, and machine learning experts who believe targeted extrahepatic delivery is the key to making RNA therapies the standard of care for a wide range of chronic diseases. We combine deep expertise in receptor biology, generative AI, and high-throughput in vivo data generation to accelerate the development of RNA therapeutics for new tissues. We are addressing a major unmet need across the industry and actively partner with pharmaceutical companies, research institutions, and biotech companies.

About the Role

We are seeking a Principal/Senior Scientist, Receptor & Cell Biology to lead and execute cell biology strategies supporting discovery and validation of receptor-mediated delivery approaches for RNA therapeutics. This role will be central to building and characterizing cellular systems used to assess receptor expression, ligand binding, internalization, trafficking, and endosomal escape across a range of target classes, including complex multipass receptors. This is a high impact and leadership role that will drive both internal and collaboration program development across the Nosis portfolio.

The ideal candidate will bring deep expertise in mammalian cell biology, assay development, and receptor pharmacology, with the ability to work cross-functionally across translational sciences, biology, chemistry, and platform teams in a fast-paced startup environment. Title will be commensurate with experience.

Scientific Responsibilities

• Design, generate, maintain, and characterize mammalian cell lines to support receptor biology and therapeutic delivery programs

• Engineer cell systems for receptor overexpression, knockout, knockdown, and deletion, including challenging target classes including complex multipass receptors

• Design and validate siRNA payloads, ensuring activity in multiple organisms

• Develop, validate, and execute receptor binding assays to evaluate ligand engagement, specificity, affinity, and competition

• Develop validate, and execute receptor internalization assays to assess uptake kinetics, trafficking dynamics, recycling, and intracellular localization

• Establish robust in vitro workflows to characterize receptor biology, expression levels, and functional response across relevant cellular and ex vivo models

• Design experiments to evaluate target-dependent uptake and cell-selective delivery mechanisms

• Analyze and interpret complex datasets from flow cytometry, microscopy, plate-based assays, and related cell-based readouts

• Maintain accurate, real-time experimental documentation in the electronic lab notebook, including protocols, raw data, and interpretation

• Collaborate closely with multidisciplinary teams across discovery biology, translational sciences, chemistry, and data science

• Present data clearly in team meetings and contribute to program strategy, experimental planning, and decision-making

Leadership Responsibilities

• Lead development of higher-content and mechanistic assays to better understand receptor binding, internalization, trafficking, and cell-specific uptake

• Contribute to prioritization of receptor targets and experimental approaches based on biological rationale, technical feasibility, and program needs

• Mentor scientists and research associates, providing technical guidance and maintaining a high bar for rigor, reproducibility, and scientific interpretation

• Identify and implement new technologies, model systems, and assay platforms that expand Nosis Bio’s cell biology capabilities

• Serve as a scientific leader across functions, helping integrate in vitro biology with in vivo and translational datasets

• Contribute to external presentations, partner discussions, and strategic scientific communications as needed

What We’re Looking For

• PhD in Cell Biology, Molecular Biology, Pharmacology, Bioengineering, or a related field

• Strong expertise in mammalian cell culture, cell line engineering, and cell-based assay development

• Deep experience working with receptor biology, including membrane proteins and ideally multipass transmembrane receptors

• Experience developing and interpreting receptor binding and internalization assays, including kinetic and mechanistic studies
  Strong experimental design skills, scientific judgment, and problem-solving ability

• Excellent communication skills and ability to work collaboratively across scientific disciplines

• Demonstrated ability to lead scientific strategy, build new capabilities, and drive complex programs forward in a cross-functional environment

Ability to work on site in our lab spaces located in Alameda, CA