Dataset Information

RhoBTB1 C-Terminal Binding Proteins in A7r5 Smooth Muscle Cells

ABSTRACT: The RhoBTB1-Cullin3 (CUL3) pathway in smooth muscle cells (SMCs) controls the ubiquitination of target proteins and through this blood pressure (BP) and arterial stiffness. We performed APEX2 proximity labelling coupled with mass spectrometry to identify RhoBTB1 interacting partners in A7R5 SMCs. We identified 59 proteins which bound to the C-terminal half of RhoBTB1, the region identified as essential for its adapter function to deliver substrates to CUL3. We examined one of these proteins in detail - RbFox2. Co-immunoprecipitation validated the interaction of RbFox2 with RhoBTB1. Expression of RbFox2 was elevated in response to inhibition of the ubiquitination-proteasomal pathway, CUL3-deficiency, and RhoBTB1 inhibition by either siRNA or angiotensin II (ANG). RbFox2 was ubiquitinated in a RhoBTB1- and CUL3-dependent manner suggesting it is regulated through the RhoBTB1-CUL3-dependent ubiquitin-proteasome pathway. Inhibition of RbFox2 impaired the actin cytoskeleton in A7R5 cells and in primary SMC from RbFox2Flox mice and decreased the levels of globular and filamentous actin. ANG increased BP and arterial stiffness of RbFox2Flox mice, but the progression of arterial stiffness was halted after SMC-specific RbFox2 deletion despite a continued rise in BP. We conclude that RhoBTB1 and its target RbFox2 is an important regulator of arterial stiffness through its actions to regulate the cytoskeleton.

INSTRUMENT(S):

ORGANISM(S): Rattus Norvegicus (rat)

TISSUE(S): Cell Culture, Aortic Smooth Muscle Cell

SUBMITTER: Curt Sigmund

LAB HEAD: Curt Sigmund

PROVIDER: PXD067797 | Pride | 2026-04-06

REPOSITORIES: Pride

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			Action	DRS
	2154_Porter_220916_Ts024_LFQ_01.mzML	Mzml
	2154_Porter_220916_Ts024_LFQ_01.mzid	Mzid
	2154_Porter_220916_Ts024_LFQ_01.pdResult	Other
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Publications

Vascular smooth muscle RbFox2 regulates the cytoskeleton and arterial stiffness by a RhoBTB1/Cullin-3 mechanism.

Kumar Gaurav G Chaihongsa Nisita N Brozoski Daniel T DT Golosova Daria D Vazirabad Ibrahim I Lu Ko-Ting KT Wackman Kelsey K KK Singh Ravi K RK Sigmund Curt D CD

JCI insight 20260402 11

The RhoBTB1/Cullin-3 (CUL3) pathway in smooth muscle cells (SMCs) controls the ubiquitination and proteasomal degradation of target proteins that regulate vasodilation, vasoconstriction, and the actin cytoskeleton and, through this, blood pressure (BP) and arterial stiffness. Using proximity labeling coupled with mass spectrometry in A7R5 SMCs, we identified proteins that bound to the C-terminal half of RhoBTB1, which functions as an adaptor to deliver substrates to CUL3. We examined the physiol ...[more]

PMID: 41926228

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