# Origins of Cell Geometry

> **NIH NIH R35** · UNIVERSITY OF CALIFORNIA, SAN FRANCISCO · 2024 · $678,955

## Abstract

Abstract
Cells are highly complex living nanomachines with beautiful structures of great precision. This is true not only
for free living organisms like ciliates or radiolarians, but also for cells inside the human body. These
complicated structures are directly linked to the physiological functions of cells, and alterations in cell geometry
are a hallmark of many disease states. Yet in most cases we have almost no information about how cells
determine their geometry at the level of organelle size and shape. Thus, understanding the origins of cell
geometry remains a fundamental unsolved problem in cell biology. Part of the challenge is that cell geometry
involves multiple spatial scales ranging from molecules up to the whole cell. Spanning this gap between
scales requires us to go beyond traditional molecular biology approaches and bring in methods from physics
and engineering. For this reason my proposal is based on an integrated combination of approaches, using
several different model organisms and cell types to address the origins of cell geometry at several different
size scales. At the level of single organelles, I will continue to probe the mechanism of flagellar length control
as a paradigm for organelle size regulation, with a focus on learning how cells can sense the length of their
flagella. At a larger scale, we will continue our development of the classic model organism, Stentor coeruleus,
as a genomic model system for analyzing global cell morphogenesis and regeneration. Using Stentor, we
intend to pursue the two linked questions of how a cell knows that is geometry has been perturbed, and what
molecules it uses to encode positional information needed to direct the re-assembly of a correct cell geometry.
Both of these questions that have general significance to all cell types but are particularly easy to study in
Stentor. Our proposed work is unified by the focus on a single question – where does geometry come from
inside a cell. We will use different model systems to address different aspects of this question, but in all cases
we will take an interdisciplinary approach that combines tools of genetics, genomics, microscopy, image
analysis, and mathematical modeling.

## Key facts

- **NIH application ID:** 10765541
- **Project number:** 2R35GM130327-06
- **Recipient organization:** UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
- **Principal Investigator:** Wallace Marshall
- **Activity code:** R35 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $678,955
- **Award type:** 2
- **Project period:** 2019-02-01 → 2029-01-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10765541

## Citation

> US National Institutes of Health, RePORTER application 10765541, Origins of Cell Geometry (2R35GM130327-06). Retrieved via AI Analytics 2026-06-11 from https://api.ai-analytics.org/grant/nih/10765541. Licensed CC0.

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