--- title: 'Cellular Biologist at Topos Bio' canonical: 'https://feeny.ai/job/cellular-biologist-topos-bio-south-san-francisco-3tdhe9fqcb2s' type: 'job' last_seen: '2026-10-19' --- # Cellular Biologist at Topos Bio - **Company:** Topos Bio - **Location:** South San Francisco, CA - **Employment:** full-time - **Work type:** onsite - **Posted:** 2026-09-30 - **Last confirmed live:** 2026-10-19 - **Apply:** https://jobs.ashbyhq.com/toposbio/8e527944-54a8-4028-804f-ea24851b3e6a ## Job description Topos Bio At Topos Bio, we're pioneering drug discovery for intrinsically disordered proteins—targets that have eluded conventional approaches in neurodegeneration, oncology, and cardiometabolic disease. We're seeking a cell biologist to develop and execute cell-based assays for validating computational predictions and supporting medicinal chemistry efforts. You'll work at the interface of disease biology, protein biophysics, and drug screening. ## What you will do - Develop and optimize mammalian cell-based assays for disordered protein targets - Execute phenotypic and reporter-based screening campaigns to validate computational hits - Characterize compound activity and support structure-activity relationship studies - Collaborate with computational scientists to integrate experimental data with modeling workflows - Establish robust assay protocols and quality control metrics ## What we are looking for - Strong foundation in mammalian cell culture and cellular assay development - Experience with disease-relevant cellular models - Ability to troubleshoot complex biological systems and optimize experimental protocols - Track record of productivity and effective collaboration ## Preferred - PhD in cell and molecular biology with focus on disease models - Industry experience in drug discovery or biotech - Experience with reporter assays and high-throughput screening platforms - Familiarity with oncology, neurodegeneration, or metabolic disease models - Track record of developing novel cellular assays or screening approaches ## About Topos Bio ## Company Overview - **One-liner**: Topos Bio is building an AI-native drug discovery platform that models intrinsically disordered proteins (IDPs) as dynamic ensembles to unlock previously "undruggable" targets in neurodegenerative diseases and cancer. - **Entity Type**: Private (Seed Stage) - **Headquarters**: San Francisco, California, United States - **Founded**: Not publicly available (likely 2024-2025 based on funding and team formation) - **Founders**: Ryan Zarcone (Co-Founder & CEO), Amir Khosrowshahi (Co-Founder & CTO), Fernando Martinez (Founding Scientist) ## Core Business - **Primary industry/industries**: Biotechnology, AI-Powered Drug Discovery, Therapeutics - **Target customers**: B2B (pharmaceutical and biotech partners) and internal pipeline for drug development; enterprise-level research institutions. - **Mission or purpose statement**: To understand and control biology in motion by modeling intrinsically disordered proteins (IDPs) as dynamic ensembles, unlocking previously "undruggable" targets for diseases like Alzheimer's, Parkinson's, and cancer. ## Products & Services - **Topos-1 Foundation Model**: An all-atom foundation model trained on a large proprietary dataset of simulation and experimental data. It generates physically realistic conformational ensembles for flexible proteins at speeds that make ensemble-level modeling practical for daily research and drug discovery. (Type: AI Model / Platform) - **AI-Native Drug Discovery Platform**: An end-to-end platform that uses Topos-1 to design small molecule and biologic therapeutics specifically for intrinsically disordered proteins (IDPs). The platform integrates proprietary data generation, computational modeling, and experimental validation. (Type: Platform / Service) - **Internal Drug Pipeline**: Topos is developing its own therapeutic candidates targeting IDPs implicated in Alzheimer's disease, Parkinson's disease, and aggressive cancers (e.g., prostate cancer). (Type: Pipeline / Therapeutics) ## Market Standing - **Valuation/Market Cap**: Not disclosed (Private company) - **Key Metric**: Total Funding of **$10.5M** (Seed Round, announced January 2026) - **Notable Investors/Partners**: Threshold (Lead), Neo, and other investors. Partners include **Gladstone Institutes** (neuroscience research) and **Dalriada Drug Discovery** (mass spectrometry and proteomics). - **Growth Signals**: - Launched its first foundation model, Topos-1, in early 2026. - Published a technical report detailing Topos-1's capabilities. - Formed a strategic partnership with Dalriada Drug Discovery in March 2026. - Headcount of 16 employees with a monthly growth rate of +11.1% (as of mid-2026). - Active job posting for a Computational Chemist. ## Competitive Advantages - **Focus on the "Undruggable"**: Targets intrinsically disordered proteins (IDPs), which represent ~33% of the human proteome and are implicated in major diseases like Alzheimer's and cancer, but are ignored by most drug discovery platforms that rely on static structures. - **Proprietary Data Moat**: Built a large, proprietary dataset of simulation and experimental data specifically for IDPs, as no public dataset exists for this purpose. This creates a significant barrier to entry for competitors. - **Ensemble Modeling Approach**: Unlike AlphaFold and other static structure predictors, Topos-1 models the full conformational ensemble of a protein, capturing its motion and dynamics. This is a fundamentally different and more accurate approach for targeting flexible proteins. - **Integrated Experimental Flywheel**: The company has built in-house experimental capabilities to test and fine-tune its AI models, creating a data flywheel that accelerates compound discovery. ## Strategic Focus - **Validate the Platform**: Continue to publish technical results and partner with leading research institutions (like Gladstone Institutes) to validate Topos-1's predictive power. - **Advance Internal Pipeline**: Progress therapeutic candidates for neurodegenerative (Alzheimer's, Parkinson's) and oncology (prostate cancer) targets toward preclinical development. - **Expand Partnerships**: Leverage the Dalriada partnership to integrate advanced proteomics data, further improving the model's accuracy and scope. - **Scale the Team**: Grow the headcount, particularly in computational chemistry and research science roles, to accelerate platform and pipeline development. ## Why Work Here - **Mission-Driven**: The opportunity to work on a fundamental problem in biology—modeling protein dynamics—with the potential to cure some of the most devastating human diseases. - **Cutting-Edge Science**: Work at the intersection of AI (generative models, foundation models) and biophysics (molecular dynamics, structural biology) on a novel approach that challenges the status quo. - **Hybrid Workspace**: The company operates with a hybrid model, allowing for a combination of remote and on-site work in San Francisco. - **Early-Stage Impact**: As a small, well-funded seed-stage company (16 employees), new hires will have significant ownership and influence over the platform and pipeline direction. - **Strong Founding Team**: Led by experienced founders and scientists from top institutions (Berkeley, Stanford, Intel, Rezo Therapeutics), with a board including notable tech and biotech figures. ## Sources 1. [toposbio.ai](https://toposbio.ai/) 2. [toposbio.ai/about](https://www.toposbio.ai/about) 3. [linkedin.com](https://www.linkedin.com/company/topos-bio) 4. [builtin.com](https://builtin.com/company/topos-bio) 5. [jobs.ashbyhq.com](https://jobs.ashbyhq.com/toposbio) ## Other roles at Topos Bio - [Computational Chemist](https://feeny.ai/job/computational-chemist-topos-bio-san-francisco-hapthyx8b447) — San Francisco, CA - [ML Research Scientist](https://feeny.ai/job/ml-research-scientist-topos-bio-san-francisco-dwwrzh13p656) — San Francisco, CA