# Viral and Cellular Determinants of HIV-1 Assembly

> **NIH NIH R01** · CINCINNATI CHILDRENS HOSP MED CTR · 2024 · $609,012

## Abstract

The major goal of this application is to define viral interactions with host pathways that are essential for the
assembly of infectious HIV-1 particles. We previously identified Rab11-FIP1C (FIP1C) as a key adaptor
protein required for HIV-1 envelope protein (Env) trafficking and particle incorporation, a finding that
established the model stating that host recycling pathways are required for particle incorporation. Recent work
from our laboratory has extended this model, defining the role of KIF16B in Env trafficking and identifying
discrete motifs within the Env cytoplasmic tail that are essential for recycling and particle incorporation.
Preliminary data presented here now identifies the tubular recycling endosome (TRE) as a major new
component of the recycling machinery involved in particle incorporation of Env. TRE components including
MICAL-L1 and EHD1 were shown to be essential for Env trafficking and incorporation into particles.
Remarkably, disruption of TRE trafficking severely depleted Env from particles, but only in those cells that
have been shown to be nonpermissive for incorporation of cytoplasmic tail (CT)-depleted Env. Thus, this
pathway holds the key to understanding the contribution of the Env CT to the recycling and particle
incorporation of Env. Experiments in Aim 1 will define essential components of the TRE that contribute to Env
trafficking, examining EHBP1, Rab10, Syndapin2, and MICAL-L1. In Aim 2, the critical role of EHD1-mediated
scission from the TRE in Env trafficking to the PM site of assembly will be defined using cellular/biochemical
and imaging approaches. A unique FAP-tagged Env construct will be employed to visualize and quantify Env
trafficking from the TRE to the PM in live cells. Aim 3 will determine the mechanisms responsible for cell type-
dependence of incorporation of Env, using a novel cell-cell fusion approach combined with identification of
host factors that interact with the Env CT. Together, the work outlined here will expand upon a productive line
of investigation that seeks to comprehensively define the mechanism of incorporation of Env into HIV-1
particles.

## Key facts

- **NIH application ID:** 11008764
- **Project number:** 1R01AI186611-01
- **Recipient organization:** CINCINNATI CHILDRENS HOSP MED CTR
- **Principal Investigator:** PAUL W. SPEARMAN
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $609,012
- **Award type:** 1
- **Project period:** 2024-05-20 → 2029-03-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/11008764

## Citation

> US National Institutes of Health, RePORTER application 11008764, Viral and Cellular Determinants of HIV-1 Assembly (1R01AI186611-01). Retrieved via AI Analytics 2026-05-26 from https://api.ai-analytics.org/grant/nih/11008764. Licensed CC0.

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