p38

P-38, often written p38, is a designation used for several distinct items in aviation, biology, and military gear. The most widely recognized are the Lockheed P-38 Lightning fighter aircraft of World War II and the p38 mitogen-activated protein kinase (MAPK) family of enzymes involved in cellular responses to stress. A less common but enduring reference is the field P-38 can opener.

The Lockheed P-38 Lightning was a twin-boom, twin-engine American fighter aircraft developed by Lockheed and designed by Clarence “Kelly” Johnson. It entered service in 1941 and saw action in both the Pacific and European theaters, serving as a long-range escort, interceptor, and reconnaissance aircraft. Its distinctive configuration, with a central nacelle and two tail booms, contributed to high speed and range for the time. Production totaled more than 10,000 units before the war’s end, making it one of the most iconic Allied fighters of the era.

The p38 MAPK family comprises serine/threonine protein kinases activated by stress signals such as cytokines, ultraviolet light, and inflammatory stimuli. They regulate gene expression, inflammation, differentiation, and apoptosis, contributing to cellular responses across many tissues. Four main isoforms—p38α, p38β, p38γ, and p38δ—exhibit overlapping but distinct roles and are studied as potential targets in inflammatory diseases and cancer therapy.

The P-38 can opener is a small, folding device issued to U.S. military personnel during World War II. About two inches long, it opens canned rations by puncturing the lid and then rolling along the edge to slice it open. It remains a common emblem of field expediency and is collected as a historical novelty.