Analysis of Three Architectures for Controlling PTP1B with Light

Photosensory
domains are powerful tools for placing proteins under
optical control, but their integration into light-sensitive chimeras
is often challenging. Many designs require structural iterations,
and direct comparisons of alternative approaches are rare. This study
uses protein tyrosine phosphatase 1B (PTP1B), an influential regulatory
enzyme, to compare three architectures for controlling PTPs with light:
a protein fusion, an insertion chimera, and a split construct. All
three designs permitted optical control of PTP1B activity in vitro (i.e., kinetic assays of purified enzyme) and in
mammalian cells; photoresponses measured under both conditions, while
different in magnitude, were linearly correlated. The fusion- and
insertion-based architectures exhibited the highest dynamic range
and maintained native localization patterns in mammalian cells. A
single insertion architecture enabled optical control of both PTP1B
and TCPTP, but not SHP2, where the analogous chimera was active but
not photoswitchable. Findings suggest that PTPs are highly tolerant
of domain insertions and support the use of in vitro screens to evaluate different optogenetic designs.