sloβ1 is a member of a family of regulatory β subunits that control the activity of the large conductance Ca²⁺-activated K⁺ channel K_Ca1.1. The family includes four members with a shared topology: two trans-membrane domains, short intracellular N- and C-termini and a large extracellular region. The four members of the family have a distinct tissue distribution with sloβ1 expressed almost exclusively in smooth muscle.

Functionally, sloβ1 increases the sensitivity of the pore-forming K_Ca1.1 subunit to Ca²⁺ and voltage and it also changes its pharmacology.

In the past few years there has been a lot of interest regarding the role of the sloβ1 subunit in the regulation of vascular tone and hypertension. Studies in sloβ1 knockout mice have shown that loss of this subunit results in systemic hypertension. Conversely, a recent study showed that a commonly found gain-of-function sloβ1 variant has a protective effect against human diastolic hypertension.