Principal Scientist

We are a vibrant and intensely mission-driven team in San Francisco, comprising members from MIT, Harvard Medical School, Roche, ETH, and Dana-Farber. We value speed and rigor, coupled with excitement, drive, and a strong work ethic. In an early-stage environment, we value people who can bring clarity to open-ended problems, take ownership of the next steps, and follow through with energy. Capable Labs is a place for ambitious, high-integrity people who want to become dramatically better. You will be surrounded by people who care intensely about the work, get close feedback from the people making scientific and company-defining decisions, and have room to own increasingly important problems. We believe excellent work should be met with meaningful reward, ownership, and trust. Responsibility is earned through contribution, not title alone: anyone who demonstrates the judgment, rigor, and follow-through to move important work forward can earn meaningful scope. About The Role You will lead cell-based assay development and execution on a dedicated night-shift schedule, with a focus on generating reliable GPCR pharmacology data that directly informs compound decisions. You will own assay quality, troubleshoot difficult biological systems, and create clean handoffs so synthesis, automation, and biology can operate as a continuous experimental loop. Responsibilities Lead the design, execution, and optimization of cell-based GPCR assays, including calcium flux, cAMP, IP1/IP accumulation, beta-arrestin recruitment, receptor internalization, membrane potential, and related readouts. Develop robust workflows across transient and stable cell systems, optimizing culture conditions, plating density, receptor expression, stimulation formats, time courses, dose-response designs, and assay windows. Use fluorescence, luminescence, HTRF/TR-FRET, BRET, ELISA, plate-reader, imaging, and related methods to characterize potency, efficacy, selectivity, kinetics, bias, and reproducibility. Set assay controls, quality standards, and troubleshooting strategies that produce interpretable, decision-ready data. Investigate noisy curves, unusual plates, inconsistent biology, or compound results that do not make sense, and resolve root causes before problems repeat. Work closely with chemists and automation engineers to connect newly synthesized compounds to biological activity and prioritize the next experiments. Document overnight work and provide clear handoffs covering results, failures, decisions, and follow-up actions for the day team. Ideal Qualifications Able and willing to work the designated night-shift schedule reliably and make sound technical decisions independently when needed. Deep hands-on experience developing and running cell-based assays in cell biology, pharmacology, molecular biology, chemical biology, neuroscience, bioengineering, screening, or a closely related area. Strong experimental judgment and a systematic approach to assay troubleshooting, reproducibility, controls, and data interpretation. Experience with GPCR signaling assays such as calcium flux, cAMP, IP1/IP accumulation, beta-arrestin, or receptor trafficking is helpful but not required. The ability to set technical direction, improve workflows, and collaborate closely with chemistry and automation teams while remaining hands-on. Clear, disciplined documentation and communication across night-to-day handoffs. Pay & Benefits In addition to the posted salary range, we offer generous equity options. Compensation will depend on the skills, experience, and scope of impact you bring. If your background, experience, or compensation needs fall outside this range, we are still open to a conversation based on the scope and impact you could bring. $500+ monthly wellness budget for training, supplements, coaching, recovery, or other tools that help you perform at your best. Healthcare: We offer a broad range of medical, dental, and vision coverage options, with Capable covering 100% of the base policy. You will also have access to HSA, FSA, and 401K plans. Healthy dinners with the team are provided daily. We support visa sponsorship where appropriate, including O-1, H-1B, J-1, TN, and other employment-based pathways. Our team is already international, with members from Canada, Pakistan, Germany, Austria, Switzerland, China, India, and the United States. Application Process Our process is fast, transparent, and personal. We care about getting to know the person behind the application. Initial application First phone screen Second phone screen In-person work trial in San Francisco: designed to give both sides a realistic sense of working together. Get to know the founding team! Apply Today Curious but not sure? Apply anyway. It takes 5 minutes, and you do not need to be actively job searching to start a conversation. Some of the best people do not map perfectly to a job description. If this sounds like a place where you could do important work, we would like to hear from you. And if someone exceptional comes to mind, send them our way here. We read every referral carefully, and if your referral joins Capable, we’ll send you a thank-you bonus. Equal Opportunity Capable is an Equal Opportunity Employer; employment with Capable is governed on the basis of merit, competence and qualifications and will not be influenced in any manner by race, color, religion, gender, national origin/ethnicity, veteran status, disability status, age, sexual orientation, gender identity, marital status, mental or physical disability or any other legally protected status. Compensation Range: $155K - $260K #J-18808-Ljbffr CAPABLE.org